cpp.md

C++

1194 (339 Easy; 653 Medium; 202 Hard) Problems listed.

#	Problem	Free?	AC Rate	Difficulty	Tags	Solutions
0001	Two Sum	Free	46%	Easy	Array Hash Table	Soln 1 Soln 2 Soln 3
0002	Add Two Numbers	Free	35%	Medium	Linked List Math	Soln 1 Soln 2
0003	Longest Substring Without Repeating Characters	Free	31%	Medium	Hash Table Two Pointers String Sliding Window	Soln 1 Soln 2
0004	Median of Two Sorted Arrays	Free	30%	Hard	Array Binary Search Divide and Conquer	Soln 1
0005	Longest Palindromic Substring	Free	30%	Medium	String Dynamic Programming	Soln 1 Soln 2
0006	ZigZag Conversion	Free	37%	Medium	String	Soln 1
0007	Reverse Integer	Free	26%	Easy	Math	Soln 1 Soln 2
0008	String to Integer (atoi)	Free	16%	Medium	Math String	Soln 1 Soln 2 Soln 3
0009	Palindrome Number	Free	49%	Easy	Math	Soln 1
0010	Regular Expression Matching	Free	27%	Hard	String Dynamic Programming Backtracking	Soln 1 Soln 2 Soln 3
0011	Container With Most Water	Free	52%	Medium	Array Two Pointers	Soln 1
0012	Integer to Roman	Free	56%	Medium	Math String	Soln 1
0013	Roman to Integer	Free	56%	Easy	Math String	Soln 1
0014	Longest Common Prefix	Free	36%	Easy	String	Soln 1
0015	3Sum	Free	27%	Medium	Array Two Pointers	Soln 1 Soln 2
0016	3Sum Closest	Free	46%	Medium	Array Two Pointers	Soln 1 Soln 2
0017	Letter Combinations of a Phone Number	Free	48%	Medium	String Backtracking	Soln 1 Soln 2
0018	4Sum	Free	34%	Medium	Array Hash Table Two Pointers	Soln 1 Soln 2
0019	Remove Nth Node From End of List	Free	35%	Medium	Linked List Two Pointers	Soln 1
0020	Valid Parentheses	Free	39%	Easy	String Stack	Soln 1
0021	Merge Two Sorted Lists	Free	55%	Easy	Linked List	Soln 1
0022	Generate Parentheses	Free	64%	Medium	String Backtracking	Soln 1 Soln 2
0023	Merge k Sorted Lists	Free	42%	Hard	Linked List Divide and Conquer Heap	Soln 1 Soln 2 Soln 3
0024	Swap Nodes in Pairs	Free	52%	Medium	Linked List	Soln 1
0025	Reverse Nodes in k-Group	Free	44%	Hard	Linked List	Soln 1
0026	Remove Duplicates from Sorted Array	Free	46%	Easy	Array Two Pointers	Soln 1
0027	Remove Element	Free	49%	Easy	Array Two Pointers	Soln 1
0028	Implement strStr()	Free	35%	Easy	Two Pointers String	Soln 1 Soln 2 Soln 3
0029	Divide Two Integers	Free	17%	Medium	Math Binary Search	Soln 1 Soln 2
0030	Substring with Concatenation of All Words	Free	26%	Hard	Hash Table Two Pointers String	Soln 1 Soln 2
0031	Next Permutation	Free	33%	Medium	Array	Soln 1 Soln 2
0032	Longest Valid Parentheses	Free	29%	Hard	String Dynamic Programming	Soln 1
0033	Search in Rotated Sorted Array	Free	35%	Medium	Array Binary Search	Soln 1 Soln 2
0034	Find First and Last Position of Element in Sorted Array	Free	37%	Medium	Array Binary Search	Soln 1 Soln 2 Soln 3 Soln 4 Soln 5
0035	Search Insert Position	Free	43%	Easy	Array Binary Search	Soln 1 Soln 2
0036	Valid Sudoku	Free	50%	Medium	Hash Table	Soln 1 Soln 2
0037	Sudoku Solver	Free	45%	Hard	Hash Table Backtracking	Soln 1
0038	Count and Say	Free	46%	Easy	String	Soln 1
0039	Combination Sum	Free	58%	Medium	Array Backtracking	Soln 1 Soln 2 Soln 3 Soln 4
0040	Combination Sum II	Free	50%	Medium	Array Backtracking	Soln 1 Soln 2
0041	First Missing Positive	Free	33%	Hard	Array	Soln 1
0042	Trapping Rain Water	Free	50%	Hard	Array Two Pointers Stack	Soln 1 Soln 2 Soln 3
0043	Multiply Strings	Free	35%	Medium	Math String	Soln 1 Soln 2
0045	Jump Game II	Free	31%	Hard	Array Greedy	Soln 1 Soln 2 Soln 3
0046	Permutations	Free	65%	Medium	Backtracking	Soln 1 Soln 2 Soln 3 Soln 4
0047	Permutations II	Free	49%	Medium	Backtracking	Soln 1 Soln 2 Soln 3
0048	Rotate Image	Free	59%	Medium	Array	Soln 1
0049	Group Anagrams	Free	58%	Medium	Hash Table String	Soln 1 Soln 2 Soln 3 Soln 4
0050	Pow(x, n)	Free	31%	Medium	Math Binary Search	Soln 1 Soln 2 Soln 3
0051	N-Queens	Free	48%	Hard	Backtracking	Soln 1 Soln 2
0052	N-Queens II	Free	59%	Hard	Backtracking	Soln 1
0053	Maximum Subarray	Free	47%	Easy	Array Divide and Conquer Dynamic Programming	Soln 1 Soln 2
0054	Spiral Matrix	Free	35%	Medium	Array	Soln 1 Soln 2
0055	Jump Game	Free	35%	Medium	Array Greedy	Soln 1 Soln 2 Soln 3
0056	Merge Intervals	Free	40%	Medium	Array Sort	Soln 1 Soln 2 Soln 3
0057	Insert Interval	Free	35%	Medium	Array Sort	Soln 1
0058	Length of Last Word	Free	33%	Easy	String	Soln 1
0059	Spiral Matrix II	Free	55%	Medium	Array	Soln 1 Soln 2
0060	Permutation Sequence	Free	39%	Hard	Math Backtracking	Soln 1
0061	Rotate List	Free	31%	Medium	Linked List Two Pointers	Soln 1
0062	Unique Paths	Free	55%	Medium	Array Dynamic Programming	Soln 1 Soln 2
0063	Unique Paths II	Free	35%	Medium	Array Dynamic Programming	Soln 1 Soln 2
0064	Minimum Path Sum	Free	56%	Medium	Array Dynamic Programming	Soln 1 Soln 2
0065	Valid Number	Free	16%	Hard	Math String	Soln 1
0066	Plus One	Free	43%	Easy	Array	Soln 1 Soln 2
0067	Add Binary	Free	46%	Easy	Math String	Soln 1 Soln 2
0068	Text Justification	Free	29%	Hard	String	Soln 1
0069	Sqrt(x)	Free	35%	Easy	Math Binary Search	Soln 1
0070	Climbing Stairs	Free	48%	Easy	Dynamic Programming	Soln 1
0071	Simplify Path	Free	33%	Medium	String Stack	Soln 1
0072	Edit Distance	Free	46%	Hard	String Dynamic Programming	Soln 1 Soln 2
0073	Set Matrix Zeroes	Free	44%	Medium	Array	Soln 1
0074	Search a 2D Matrix	Free	37%	Medium	Array Binary Search	Soln 1 Soln 2
0075	Sort Colors	Free	49%	Medium	Array Two Pointers Sort	Soln 1 Soln 2 Soln 3
0077	Combinations	Free	56%	Medium	Backtracking	Soln 1 Soln 2 Soln 3
0078	Subsets	Free	64%	Medium	Array Backtracking Bit Manipulation	Soln 1 Soln 2
0079	Word Search	Free	36%	Medium	Array Backtracking	Soln 1
0080	Remove Duplicates from Sorted Array II	Free	45%	Medium	Array Two Pointers	Soln 1
0081	Search in Rotated Sorted Array II	Free	33%	Medium	Array Binary Search	Soln 1
0082	Remove Duplicates from Sorted List II	Free	38%	Medium	Linked List	Soln 1
0083	Remove Duplicates from Sorted List	Free	46%	Easy	Linked List	Soln 1
0084	Largest Rectangle in Histogram	Free	36%	Hard	Array Stack	Soln 1
0086	Partition List	Free	43%	Medium	Linked List Two Pointers	Soln 1
0087	Scramble String	Free	34%	Hard	String Dynamic Programming	Soln 1
0088	Merge Sorted Array	Free	40%	Easy	Array Two Pointers	Soln 1 Soln 2
0089	Gray Code	Free	50%	Medium	Backtracking	Soln 1 Soln 2 Soln 3
0090	Subsets II	Free	48%	Medium	Array Backtracking	Soln 1
0091	Decode Ways	Free	26%	Medium	String Dynamic Programming	Soln 1 Soln 2
0092	Reverse Linked List II	Free	40%	Medium	Linked List	Soln 1
0093	Restore IP Addresses	Free	37%	Medium	String Backtracking	Soln 1
0094	Binary Tree Inorder Traversal	Free	65%	Medium	Hash Table Stack Tree	Soln 1 Soln 2
0095	Unique Binary Search Trees II	Free	42%	Medium	Dynamic Programming Tree	Soln 1
0096	Unique Binary Search Trees	Free	54%	Medium	Dynamic Programming Tree	Soln 1 Soln 2
0097	Interleaving String	Free	32%	Hard	String Dynamic Programming	Soln 1 Soln 2
0098	Validate Binary Search Tree	Free	28%	Medium	Tree Depth-first Search	Soln 1 Soln 2 Soln 3
0099	Recover Binary Search Tree	Free	42%	Hard	Tree Depth-first Search	Soln 1 Soln 2 Soln 3
0100	Same Tree	Free	54%	Easy	Tree Depth-first Search	Soln 1
0101	Symmetric Tree	Free	48%	Easy	Tree Depth-first Search Breadth-first Search	Soln 1
0102	Binary Tree Level Order Traversal	Free	56%	Medium	Tree Breadth-first Search	Soln 1 Soln 2 Soln 3
0103	Binary Tree Zigzag Level Order Traversal	Free	49%	Medium	Stack Tree Breadth-first Search	Soln 1 Soln 2
0104	Maximum Depth of Binary Tree	Free	67%	Easy	Tree Depth-first Search	Soln 1
0105	Construct Binary Tree from Preorder and Inorder Traversal	Free	51%	Medium	Array Tree Depth-first Search	Soln 1 Soln 2
0106	Construct Binary Tree from Inorder and Postorder Traversal	Free	49%	Medium	Array Tree Depth-first Search	Soln 1
0107	Binary Tree Level Order Traversal II	Free	55%	Easy	Tree Breadth-first Search	Soln 1
0108	Convert Sorted Array to Binary Search Tree	Free	59%	Easy	Tree Depth-first Search	Soln 1 Soln 2
0109	Convert Sorted List to Binary Search Tree	Free	49%	Medium	Linked List Depth-first Search	Soln 1 Soln 2
0110	Balanced Binary Tree	Free	44%	Easy	Tree Depth-first Search	Soln 1
0111	Minimum Depth of Binary Tree	Free	39%	Easy	Tree Depth-first Search Breadth-first Search	Soln 1
0112	Path Sum	Free	42%	Easy	Tree Depth-first Search	Soln 1 Soln 2
0113	Path Sum II	Free	48%	Medium	Tree Depth-first Search	Soln 1 Soln 2
0114	Flatten Binary Tree to Linked List	Free	51%	Medium	Tree Depth-first Search	Soln 1 Soln 2 Soln 3
0115	Distinct Subsequences	Free	39%	Hard	String Dynamic Programming	Soln 1 Soln 2
0116	Populating Next Right Pointers in Each Node	Free	48%	Medium	Tree Depth-first Search	Soln 1 Soln 2
0117	Populating Next Right Pointers in Each Node II	Free	40%	Medium	Tree Depth-first Search	Soln 1 Soln 2
0118	Pascal's Triangle	Free	54%	Easy	Array	Soln 1
0119	Pascal's Triangle II	Free	52%	Easy	Array	Soln 1
0120	Triangle	Free	45%	Medium	Array Dynamic Programming	Soln 1 Soln 2
0121	Best Time to Buy and Sell Stock	Free	51%	Easy	Array Dynamic Programming	Soln 1 Soln 2
0122	Best Time to Buy and Sell Stock II	Free	58%	Easy	Array Greedy	Soln 1
0123	Best Time to Buy and Sell Stock III	Free	39%	Hard	Array Dynamic Programming	Soln 1
0125	Valid Palindrome	Free	38%	Easy	Two Pointers String	Soln 1
0126	Word Ladder II	Free	23%	Hard	Array String Backtracking Breadth-first Search	Soln 1
0127	Word Ladder	Free	31%	Medium	Breadth-first Search	Soln 1 Soln 2 Soln 3 Soln 4
0128	Longest Consecutive Sequence	Free	46%	Hard	Array Union Find	Soln 1 Soln 2 Soln 3
0129	Sum Root to Leaf Numbers	Free	50%	Medium	Tree Depth-first Search	Soln 1
0130	Surrounded Regions	Free	29%	Medium	Depth-first Search Breadth-first Search Union Find	Soln 1 Soln 2 Soln 3
0131	Palindrome Partitioning	Free	49%	Medium	Backtracking	Soln 1
0132	Palindrome Partitioning II	Free	31%	Hard	Dynamic Programming	Soln 1
0133	Clone Graph	Free	38%	Medium	Depth-first Search Breadth-first Search Graph	Soln 1 Soln 2
0134	Gas Station	Free	41%	Medium	Greedy	Soln 1 Soln 2
0135	Candy	Free	32%	Hard	Greedy	Soln 1 Soln 2
0136	Single Number	Free	66%	Easy	Hash Table Bit Manipulation	Soln 1 Soln 2 Soln 3
0137	Single Number II	Free	53%	Medium	Bit Manipulation	Soln 1 Soln 2 Soln 3
0138	Copy List with Random Pointer	Free	39%	Medium	Hash Table Linked List	Soln 1 Soln 2
0139	Word Break	Free	41%	Medium	Dynamic Programming	Soln 1 Soln 2 Soln 3
0141	Linked List Cycle	Free	42%	Easy	Linked List Two Pointers	Soln 1 Soln 2 Soln 3
0142	Linked List Cycle II	Free	39%	Medium	Linked List Two Pointers	Soln 1
0143	Reorder List	Free	40%	Medium	Linked List	Soln 1
0144	Binary Tree Preorder Traversal	Free	57%	Medium	Stack Tree	Soln 1 Soln 2 Soln 3
0145	Binary Tree Postorder Traversal	Free	57%	Medium	Stack Tree	Soln 1 Soln 2 Soln 3
0146	LRU Cache	Free	35%	Medium	Design	Soln 1
0147	Insertion Sort List	Free	44%	Medium	Linked List Sort	Soln 1
0148	Sort List	Free	45%	Medium	Linked List Sort	Soln 1 Soln 2 Soln 3 Soln 4
0149	Max Points on a Line	Free	17%	Hard	Hash Table Math	Soln 1
0150	Evaluate Reverse Polish Notation	Free	37%	Medium	Stack	Soln 1 Soln 2
0151	Reverse Words in a String	Free	23%	Medium	String	Soln 1 Soln 2 Soln 3
0152	Maximum Product Subarray	Free	32%	Medium	Array Dynamic Programming	Soln 1 Soln 2 Soln 3
0153	Find Minimum in Rotated Sorted Array	Free	46%	Medium	Array Binary Search	Soln 1 Soln 2
0154	Find Minimum in Rotated Sorted Array II	Free	42%	Hard	Array Binary Search	Soln 1 Soln 2
0155	Min Stack	Free	46%	Easy	Stack Design	Soln 1
0157	Read N Characters Given Read4	Paid	37%	Easy		Soln 1
0158	Read N Characters Given Read4 II - Call multiple times	Paid	36%	Hard		Soln 1
0159	Longest Substring with At Most Two Distinct Characters	Paid	50%	Medium		Soln 1
0160	Intersection of Two Linked Lists	Free	42%	Easy	Linked List	Soln 1 Soln 2
0161	One Edit Distance	Paid	33%	Medium		Soln 1
0162	Find Peak Element	Free	44%	Medium	Array Binary Search	Soln 1 Soln 2 Soln 3
0163	Missing Ranges	Paid	25%	Easy		Soln 1 Soln 2
0164	Maximum Gap	Free	36%	Hard	Sort	Soln 1
0165	Compare Version Numbers	Free	30%	Medium	String	Soln 1
0166	Fraction to Recurring Decimal	Free	22%	Medium	Hash Table Math	Soln 1 Soln 2
0167	Two Sum II - Input array is sorted	Free	55%	Easy	Array Two Pointers Binary Search	Soln 1 Soln 2
0168	Excel Sheet Column Title	Free	31%	Easy	Math	Soln 1
0169	Majority Element	Free	60%	Easy	Array Divide and Conquer Bit Manipulation	Soln 1 Soln 2
0170	Two Sum III - Data structure design	Paid	35%	Easy		Soln 1 Soln 2
0171	Excel Sheet Column Number	Free	57%	Easy	Math	Soln 1
0172	Factorial Trailing Zeroes	Free	38%	Easy	Math	Soln 1
0173	Binary Search Tree Iterator	Free	58%	Medium	Stack Tree Design	Soln 1 Soln 2 Soln 3
0174	Dungeon Game	Free	33%	Hard	Binary Search Dynamic Programming	Soln 1
0179	Largest Number	Free	30%	Medium	Sort	Soln 1
0186	Reverse Words in a String II	Paid	45%	Medium		Soln 1
0187	Repeated DNA Sequences	Free	41%	Medium	Hash Table Bit Manipulation	Soln 1 Soln 2
0189	Rotate Array	Free	36%	Medium	Array	Soln 1
0190	Reverse Bits	Free	41%	Easy	Bit Manipulation	Soln 1 Soln 2
0191	Number of 1 Bits	Free	51%	Easy	Bit Manipulation	Soln 1
0198	House Robber	Free	43%	Easy	Dynamic Programming	Soln 1 Soln 2
0199	Binary Tree Right Side View	Free	55%	Medium	Tree Depth-first Search Breadth-first Search	Soln 1
0200	Number of Islands	Free	48%	Medium	Depth-first Search Breadth-first Search Union Find	Soln 1 Soln 2
0201	Bitwise AND of Numbers Range	Free	40%	Medium	Bit Manipulation	Soln 1
0202	Happy Number	Free	51%	Easy	Hash Table Math	Soln 1 Soln 2
0203	Remove Linked List Elements	Free	39%	Easy	Linked List	Soln 1 Soln 2
0204	Count Primes	Free	32%	Easy	Hash Table Math	Soln 1 Soln 2
0205	Isomorphic Strings	Free	40%	Easy	Hash Table	Soln 1 Soln 2
0206	Reverse Linked List	Free	64%	Easy	Linked List	Soln 1 Soln 2 Soln 3
0207	Course Schedule	Free	44%	Medium	Depth-first Search Breadth-first Search Graph Topological Sort	Soln 1 Soln 2 Soln 3
0208	Implement Trie (Prefix Tree)	Free	51%	Medium	Design Trie	Soln 1 Soln 2 Soln 3
0209	Minimum Size Subarray Sum	Free	39%	Medium	Array Two Pointers Binary Search	Soln 1 Soln 2
0210	Course Schedule II	Free	42%	Medium	Depth-first Search Breadth-first Search Graph Topological Sort	Soln 1 Soln 2 Soln 3 Soln 4
0211	Design Add and Search Words Data Structure	Free	39%	Medium	Backtracking Design Trie	Soln 1
0212	Word Search II	Free	36%	Hard	Backtracking Trie	Soln 1
0213	House Robber II	Free	37%	Medium	Dynamic Programming	Soln 1 Soln 2
0214	Shortest Palindrome	Free	30%	Hard	String	Soln 1
0215	Kth Largest Element in an Array	Free	57%	Medium	Divide and Conquer Heap	Soln 1 Soln 2
0216	Combination Sum III	Free	60%	Medium	Array Backtracking	Soln 1
0217	Contains Duplicate	Free	56%	Easy	Array Hash Table	Soln 1 Soln 2 Soln 3
0218	The Skyline Problem	Free	36%	Hard	Divide and Conquer Heap Binary Indexed Tree Segment Tree Line Sweep	Soln 1
0219	Contains Duplicate II	Free	38%	Easy	Array Hash Table	Soln 1
0220	Contains Duplicate III	Free	21%	Medium	Sort Ordered Map	Soln 1
0221	Maximal Square	Free	38%	Medium	Dynamic Programming	Soln 1 Soln 2
0222	Count Complete Tree Nodes	Free	48%	Medium	Binary Search Tree	Soln 1 Soln 2
0224	Basic Calculator	Free	38%	Hard	Math Stack	Soln 1
0225	Implement Stack using Queues	Free	47%	Easy	Stack Design	Soln 1 Soln 2
0226	Invert Binary Tree	Free	66%	Easy	Tree	Soln 1 Soln 2
0227	Basic Calculator II	Free	38%	Medium	String	Soln 1
0228	Summary Ranges	Free	42%	Easy	Array	Soln 1 Soln 2
0229	Majority Element II	Free	38%	Medium	Array	Soln 1
0230	Kth Smallest Element in a BST	Free	62%	Medium	Binary Search Tree	Soln 1 Soln 2
0231	Power of Two	Free	44%	Easy	Math Bit Manipulation	Soln 1
0232	Implement Queue using Stacks	Free	51%	Easy	Stack Design	Soln 1 Soln 2
0233	Number of Digit One	Free	32%	Hard	Math	Soln 1
0234	Palindrome Linked List	Free	40%	Easy	Linked List Two Pointers	Soln 1 Soln 2
0235	Lowest Common Ancestor of a Binary Search Tree	Free	51%	Easy	Tree	Soln 1
0236	Lowest Common Ancestor of a Binary Tree	Free	48%	Medium	Tree	Soln 1 Soln 2
0237	Delete Node in a Linked List	Free	66%	Easy	Linked List	Soln 1
0238	Product of Array Except Self	Free	61%	Medium	Array	Soln 1 Soln 2
0239	Sliding Window Maximum	Free	44%	Hard	Heap Sliding Window	Soln 1
0240	Search a 2D Matrix II	Free	44%	Medium	Binary Search Divide and Conquer	Soln 1 Soln 2
0241	Different Ways to Add Parentheses	Free	57%	Medium	Divide and Conquer	Soln 1 Soln 2 Soln 3 Soln 4
0242	Valid Anagram	Free	58%	Easy	Hash Table Sort	Soln 1 Soln 2 Soln 3 Soln 4
0243	Shortest Word Distance	Paid	62%	Easy		Soln 1 Soln 2 Soln 3
0244	Shortest Word Distance II	Paid	53%	Medium		Soln 1 Soln 2
0245	Shortest Word Distance III	Paid	56%	Medium		Soln 1
0246	Strobogrammatic Number	Paid	45%	Easy		Soln 1
0247	Strobogrammatic Number II	Paid	48%	Medium		Soln 1 Soln 2
0248	Strobogrammatic Number III	Paid	40%	Hard		Soln 1 Soln 2
0249	Group Shifted Strings	Paid	57%	Medium		Soln 1
0250	Count Univalue Subtrees	Paid	53%	Medium		Soln 1
0251	Flatten 2D Vector	Paid	46%	Medium		Soln 1
0252	Meeting Rooms	Paid	55%	Easy		Soln 1
0253	Meeting Rooms II	Paid	46%	Medium		Soln 1 Soln 2 Soln 3 Soln 4 Soln 5
0254	Factor Combinations	Paid	47%	Medium		Soln 1 Soln 2
0255	Verify Preorder Sequence in Binary Search Tree	Paid	46%	Medium		Soln 1
0256	Paint House	Paid	53%	Medium		Soln 1
0257	Binary Tree Paths	Free	53%	Easy	Tree Depth-first Search	Soln 1
0258	Add Digits	Free	58%	Easy	Math	Soln 1
0259	3Sum Smaller	Paid	48%	Medium		Soln 1
0260	Single Number III	Free	65%	Medium	Bit Manipulation	Soln 1 Soln 2
0261	Graph Valid Tree	Paid	43%	Medium		Soln 1
0263	Ugly Number	Free	42%	Easy	Math	Soln 1 Soln 2
0264	Ugly Number II	Free	43%	Medium	Math Dynamic Programming Heap	Soln 1
0266	Palindrome Permutation	Paid	62%	Easy		Soln 1 Soln 2
0267	Palindrome Permutation II	Paid	37%	Medium		Soln 1
0268	Missing Number	Free	53%	Easy	Array Math Bit Manipulation	Soln 1
0270	Closest Binary Search Tree Value	Paid	49%	Easy		Soln 1
0271	Encode and Decode Strings	Paid	32%	Medium		Soln 1
0272	Closest Binary Search Tree Value II	Paid	51%	Hard		Soln 1
0273	Integer to English Words	Free	28%	Hard	Math String	Soln 1
0274	H-Index	Free	36%	Medium	Hash Table Sort	Soln 1 Soln 2
0275	H-Index II	Free	36%	Medium	Binary Search	Soln 1 Soln 2
0276	Paint Fence	Paid	39%	Easy		Soln 1
0277	Find the Celebrity	Paid	43%	Medium		Soln 1 Soln 2
0278	First Bad Version	Free	37%	Easy	Binary Search	Soln 1 Soln 2
0279	Perfect Squares	Free	48%	Medium	Math Dynamic Programming Breadth-first Search	Soln 1 Soln 2 Soln 3 Soln 4 Soln 5
0280	Wiggle Sort	Paid	64%	Medium		Soln 1 Soln 2
0281	Zigzag Iterator	Paid	59%	Medium		Soln 1
0282	Expression Add Operators	Free	36%	Hard	Divide and Conquer	Soln 1 Soln 2
0283	Move Zeroes	Free	58%	Easy	Array Two Pointers	Soln 1 Soln 2
0284	Peeking Iterator	Free	47%	Medium	Design	Soln 1
0285	Inorder Successor in BST	Paid	42%	Medium		Soln 1 Soln 2 Soln 3 Soln 4
0286	Walls and Gates	Paid	56%	Medium		Soln 1 Soln 2 Soln 3
0287	Find the Duplicate Number	Free	57%	Medium	Array Two Pointers Binary Search	Soln 1 Soln 2 Soln 3
0288	Unique Word Abbreviation	Paid	23%	Medium		Soln 1 Soln 2
0289	Game of Life	Free	56%	Medium	Array	Soln 1
0290	Word Pattern	Free	38%	Easy	Hash Table	Soln 1
0292	Nim Game	Free	55%	Easy	Brainteaser Minimax	Soln 1
0293	Flip Game	Paid	61%	Easy		Soln 1
0294	Flip Game II	Paid	50%	Medium		Soln 1
0295	Find Median from Data Stream	Free	46%	Hard	Heap Design	Soln 1
0296	Best Meeting Point	Paid	58%	Hard		Soln 1
0297	Serialize and Deserialize Binary Tree	Free	49%	Hard	Tree Design	Soln 1 Soln 2
0298	Binary Tree Longest Consecutive Sequence	Paid	48%	Medium		Soln 1 Soln 2 Soln 3
0299	Bulls and Cows	Free	44%	Medium	Hash Table	Soln 1 Soln 2
0300	Longest Increasing Subsequence	Free	43%	Medium	Binary Search Dynamic Programming	Soln 1 Soln 2 Soln 3 Soln 4
0301	Remove Invalid Parentheses	Free	44%	Hard	Depth-first Search Breadth-first Search	Soln 1
0302	Smallest Rectangle Enclosing Black Pixels	Paid	52%	Hard		Soln 1
0303	Range Sum Query - Immutable	Free	46%	Easy	Dynamic Programming	Soln 1
0304	Range Sum Query 2D - Immutable	Free	40%	Medium	Dynamic Programming	Soln 1
0305	Number of Islands II	Paid	40%	Hard		Soln 1 Soln 2
0306	Additive Number	Free	29%	Medium	Backtracking	Soln 1
0307	Range Sum Query - Mutable	Free	36%	Medium	Binary Indexed Tree Segment Tree	Soln 1 Soln 2 Soln 3 Soln 4 Soln 5
0308	Range Sum Query 2D - Mutable	Paid	37%	Hard		Soln 1 Soln 2
0309	Best Time to Buy and Sell Stock with Cooldown	Free	48%	Medium	Dynamic Programming	Soln 1 Soln 2
0310	Minimum Height Trees	Free	34%	Medium	Breadth-first Search Graph	Soln 1
0311	Sparse Matrix Multiplication	Paid	63%	Medium		Soln 1 Soln 2 Soln 3
0312	Burst Balloons	Free	53%	Hard	Divide and Conquer Dynamic Programming	Soln 1
0313	Super Ugly Number	Free	46%	Medium	Math Heap	Soln 1
0314	Binary Tree Vertical Order Traversal	Paid	46%	Medium		Soln 1
0316	Remove Duplicate Letters	Free	39%	Medium	Stack Greedy	Soln 1 Soln 2
0318	Maximum Product of Word Lengths	Free	52%	Medium	Bit Manipulation	Soln 1 Soln 2 Soln 3
0319	Bulb Switcher	Free	45%	Medium	Math Brainteaser	Soln 1
0320	Generalized Abbreviation	Paid	53%	Medium		Soln 1 Soln 2
0322	Coin Change	Free	37%	Medium	Dynamic Programming	Soln 1
0323	Number of Connected Components in an Undirected Graph	Paid	57%	Medium		Soln 1
0325	Maximum Size Subarray Sum Equals k	Paid	47%	Medium		Soln 1 Soln 2
0326	Power of Three	Free	42%	Easy	Math	Soln 1
0328	Odd Even Linked List	Free	57%	Medium	Linked List	Soln 1 Soln 2
0329	Longest Increasing Path in a Matrix	Free	44%	Hard	Depth-first Search Topological Sort Memoization	Soln 1 Soln 2
0330	Patching Array	Free	35%	Hard	Greedy	Soln 1
0331	Verify Preorder Serialization of a Binary Tree	Free	41%	Medium	Stack
0332	Reconstruct Itinerary	Free	37%	Medium	Depth-first Search Graph	Soln 1 Soln 2
0333	Largest BST Subtree	Paid	37%	Medium		Soln 1 Soln 2
0334	Increasing Triplet Subsequence	Free	40%	Medium		Soln 1 Soln 2
0337	House Robber III	Free	52%	Medium	Tree Depth-first Search	Soln 1 Soln 2
0338	Counting Bits	Free	70%	Medium	Dynamic Programming Bit Manipulation	Soln 1 Soln 2 Soln 3
0339	Nested List Weight Sum	Paid	75%	Easy		Soln 1
0340	Longest Substring with At Most K Distinct Characters	Paid	45%	Hard		Soln 1
0341	Flatten Nested List Iterator	Free	54%	Medium	Stack Design	Soln 1 Soln 2
0342	Power of Four	Free	41%	Easy	Bit Manipulation	Soln 1
0343	Integer Break	Free	51%	Medium	Math Dynamic Programming	Soln 1
0344	Reverse String	Free	70%	Easy	Two Pointers String	Soln 1 Soln 2
0345	Reverse Vowels of a String	Free	45%	Easy	Two Pointers String	Soln 1 Soln 2
0346	Moving Average from Data Stream	Paid	73%	Easy		Soln 1
0347	Top K Frequent Elements	Free	62%	Medium	Hash Table Heap	Soln 1
0348	Design Tic-Tac-Toe	Paid	55%	Medium		Soln 1
0349	Intersection of Two Arrays	Free	64%	Easy	Hash Table Two Pointers Binary Search Sort	Soln 1 Soln 2
0350	Intersection of Two Arrays II	Free	52%	Easy	Hash Table Two Pointers Binary Search Sort	Soln 1 Soln 2
0352	Data Stream as Disjoint Intervals	Free	48%	Hard	Binary Search Ordered Map	Soln 1 Soln 2 Soln 3 Soln 4
0353	Design Snake Game	Paid	35%	Medium		Soln 1
0354	Russian Doll Envelopes	Free	36%	Hard	Binary Search Dynamic Programming	Soln 1 Soln 2
0356	Line Reflection	Paid	32%	Medium		Soln 1 Soln 2
0357	Count Numbers with Unique Digits	Free	49%	Medium	Math Dynamic Programming Backtracking	Soln 1
0358	Rearrange String k Distance Apart	Paid	35%	Hard		Soln 1
0359	Logger Rate Limiter	Paid	72%	Easy		Soln 1
0360	Sort Transformed Array	Paid	49%	Medium		Soln 1
0361	Bomb Enemy	Paid	46%	Medium		Soln 1
0362	Design Hit Counter	Paid	65%	Medium		Soln 1 Soln 2
0363	Max Sum of Rectangle No Larger Than K	Free	38%	Hard	Binary Search Dynamic Programming Queue	Soln 1 Soln 2
0364	Nested List Weight Sum II	Paid	63%	Medium		Soln 1 Soln 2
0366	Find Leaves of Binary Tree	Paid	71%	Medium		Soln 1 Soln 2 Soln 3
0367	Valid Perfect Square	Free	42%	Easy	Math Binary Search	Soln 1 Soln 2
0368	Largest Divisible Subset	Free	38%	Medium	Math Dynamic Programming	Soln 1 Soln 2 Soln 3
0369	Plus One Linked List	Paid	59%	Medium		Soln 1 Soln 2 Soln 3
0370	Range Addition	Paid	63%	Medium		Soln 1 Soln 2
0371	Sum of Two Integers	Free	51%	Medium	Bit Manipulation	Soln 1
0372	Super Pow	Free	37%	Medium	Math	Soln 1
0374	Guess Number Higher or Lower	Free	44%	Easy	Binary Search	Soln 1
0375	Guess Number Higher or Lower II	Free	42%	Medium	Dynamic Programming Minimax	Soln 1 Soln 2
0376	Wiggle Subsequence	Free	40%	Medium	Dynamic Programming Greedy	Soln 1 Soln 2
0377	Combination Sum IV	Free	46%	Medium	Dynamic Programming	Soln 1
0378	Kth Smallest Element in a Sorted Matrix	Free	56%	Medium	Binary Search Heap	Soln 1
0379	Design Phone Directory	Paid	47%	Medium		Soln 1 Soln 2
0380	Insert Delete GetRandom O(1)	Free	48%	Medium	Array Hash Table Design	Soln 1 Soln 2
0381	Insert Delete GetRandom O(1) - Duplicates allowed	Free	35%	Hard	Array Hash Table Design	Soln 1
0382	Linked List Random Node	Free	54%	Medium	Reservoir Sampling	Soln 1 Soln 2 Soln 3
0383	Ransom Note	Free	53%	Easy	String	Soln 1
0384	Shuffle an Array	Free	54%	Medium		Soln 1
0385	Mini Parser	Free	34%	Medium	String Stack	Soln 1
0386	Lexicographical Numbers	Free	53%	Medium		Soln 1 Soln 2
0387	First Unique Character in a String	Free	54%	Easy	Hash Table String	Soln 1 Soln 2
0388	Longest Absolute File Path	Free	42%	Medium		Soln 1
0389	Find the Difference	Free	58%	Easy	Hash Table Bit Manipulation	Soln 1 Soln 2
0391	Perfect Rectangle	Free	31%	Hard	Line Sweep	Soln 1
0392	Is Subsequence	Free	49%	Easy	Binary Search Dynamic Programming Greedy	Soln 1
0393	UTF-8 Validation	Free	38%	Medium	Bit Manipulation
0394	Decode String	Free	52%	Medium	Stack Depth-first Search	Soln 1 Soln 2
0395	Longest Substring with At Least K Repeating Characters	Free	43%	Medium		Soln 1 Soln 2
0396	Rotate Function	Free	37%	Medium	Math	Soln 1 Soln 2
0397	Integer Replacement	Free	33%	Medium	Math Bit Manipulation	Soln 1 Soln 2
0398	Random Pick Index	Free	57%	Medium	Reservoir Sampling	Soln 1 Soln 2 Soln 3 Soln 4
0399	Evaluate Division	Free	54%	Medium	Union Find Graph	Soln 1 Soln 2
0400	Nth Digit	Free	32%	Medium	Math	Soln 1
0401	Binary Watch	Free	48%	Easy	Backtracking Bit Manipulation	Soln 1 Soln 2
0402	Remove K Digits	Free	29%	Medium	Stack Greedy	Soln 1 Soln 2
0403	Frog Jump	Free	41%	Hard	Dynamic Programming	Soln 1 Soln 2 Soln 3
0404	Sum of Left Leaves	Free	52%	Easy	Tree	Soln 1
0405	Convert a Number to Hexadecimal	Free	44%	Easy	Bit Manipulation	Soln 1
0406	Queue Reconstruction by Height	Free	68%	Medium	Greedy	Soln 1 Soln 2 Soln 3
0407	Trapping Rain Water II	Free	43%	Hard	Heap Breadth-first Search	Soln 1 Soln 2
0408	Valid Word Abbreviation	Paid	31%	Easy		Soln 1 Soln 2
0409	Longest Palindrome	Free	52%	Easy	Hash Table	Soln 1
0410	Split Array Largest Sum	Free	46%	Hard	Binary Search Dynamic Programming	Soln 1
0412	Fizz Buzz	Free	63%	Easy		Soln 1
0413	Arithmetic Slices	Free	58%	Medium	Math Dynamic Programming	Soln 1 Soln 2 Soln 3
0414	Third Maximum Number	Free	31%	Easy	Array	Soln 1 Soln 2
0415	Add Strings	Free	48%	Easy	String	Soln 1 Soln 2
0416	Partition Equal Subset Sum	Free	45%	Medium	Dynamic Programming	Soln 1 Soln 2 Soln 3 Soln 4 Soln 5 Soln 6
0417	Pacific Atlantic Water Flow	Free	42%	Medium	Depth-first Search Breadth-first Search	Soln 1 Soln 2
0418	Sentence Screen Fitting	Paid	33%	Medium		Soln 1
0419	Battleships in a Board	Free	71%	Medium		Soln 1
0421	Maximum XOR of Two Numbers in an Array	Free	54%	Medium	Bit Manipulation Trie	Soln 1
0422	Valid Word Square	Paid	38%	Easy		Soln 1 Soln 2
0424	Longest Repeating Character Replacement	Free	48%	Medium	Two Pointers Sliding Window	Soln 1
0425	Word Squares	Paid	50%	Hard		Soln 1
0426	Convert Binary Search Tree to Sorted Doubly Linked List	Paid	60%	Medium		Soln 1 Soln 2
0428	Serialize and Deserialize N-ary Tree	Paid	61%	Hard		Soln 1 Soln 2
0429	N-ary Tree Level Order Traversal	Free	66%	Medium	Tree Breadth-first Search	Soln 1 Soln 2
0430	Flatten a Multilevel Doubly Linked List	Free	56%	Medium	Linked List Depth-first Search	Soln 1 Soln 2 Soln 3 Soln 4
0433	Minimum Genetic Mutation	Free	43%	Medium		Soln 1
0434	Number of Segments in a String	Free	38%	Easy	String	Soln 1
0435	Non-overlapping Intervals	Free	44%	Medium	Greedy	Soln 1
0436	Find Right Interval	Free	48%	Medium	Binary Search	Soln 1
0437	Path Sum III	Free	48%	Medium	Tree	Soln 1 Soln 2
0438	Find All Anagrams in a String	Free	44%	Medium	Hash Table	Soln 1 Soln 2 Soln 3
0439	Ternary Expression Parser	Paid	56%	Medium		Soln 1 Soln 2
0441	Arranging Coins	Free	42%	Easy	Math Binary Search	Soln 1 Soln 2
0442	Find All Duplicates in an Array	Free	68%	Medium	Array	Soln 1 Soln 2
0443	String Compression	Free	43%	Medium	String	Soln 1
0444	Sequence Reconstruction	Paid	23%	Medium		Soln 1 Soln 2
0445	Add Two Numbers II	Free	56%	Medium	Linked List	Soln 1 Soln 2 Soln 3
0446	Arithmetic Slices II - Subsequence	Free	33%	Hard	Dynamic Programming	Soln 1
0447	Number of Boomerangs	Free	52%	Medium	Hash Table	Soln 1
0448	Find All Numbers Disappeared in an Array	Free	56%	Easy	Array	Soln 1
0449	Serialize and Deserialize BST	Free	54%	Medium	Tree	Soln 1
0450	Delete Node in a BST	Free	45%	Medium	Tree	Soln 1 Soln 2
0451	Sort Characters By Frequency	Free	64%	Medium	Hash Table Heap	Soln 1
0452	Minimum Number of Arrows to Burst Balloons	Free	50%	Medium	Greedy	Soln 1
0453	Minimum Moves to Equal Array Elements	Free	51%	Easy	Math	Soln 1
0454	4Sum II	Free	54%	Medium	Hash Table Binary Search	Soln 1 Soln 2
0455	Assign Cookies	Free	50%	Easy	Greedy	Soln 1
0456	132 Pattern	Free	31%	Medium	Stack	Soln 1
0457	Circular Array Loop	Free	30%	Medium	Array Two Pointers	Soln 1
0459	Repeated Substring Pattern	Free	43%	Easy	String	Soln 1
0461	Hamming Distance	Free	73%	Easy	Bit Manipulation	Soln 1 Soln 2 Soln 3
0462	Minimum Moves to Equal Array Elements II	Free	54%	Medium	Math	Soln 1
0463	Island Perimeter	Free	66%	Easy	Hash Table	Soln 1
0464	Can I Win	Free	29%	Medium	Dynamic Programming Minimax	Soln 1 Soln 2 Soln 3
0465	Optimal Account Balancing	Paid	48%	Hard		Soln 1
0466	Count The Repetitions	Free	29%	Hard	Dynamic Programming	Soln 1
0467	Unique Substrings in Wraparound String	Free	36%	Medium	Dynamic Programming	Soln 1
0469	Convex Polygon	Paid	37%	Medium		Soln 1
0470	Implement Rand10() Using Rand7()	Free	46%	Medium	Random Rejection Sampling	Soln 1
0471	Encode String with Shortest Length	Paid	49%	Hard		Soln 1 Soln 2
0473	Matchsticks to Square	Free	38%	Medium	Depth-first Search	Soln 1
0474	Ones and Zeroes	Free	43%	Medium	Dynamic Programming	Soln 1
0475	Heaters	Free	33%	Medium	Binary Search	Soln 1 Soln 2 Soln 3
0476	Number Complement	Free	65%	Easy	Bit Manipulation	Soln 1 Soln 2
0477	Total Hamming Distance	Free	51%	Medium	Bit Manipulation	Soln 1 Soln 2 Soln 3
0480	Sliding Window Median	Free	38%	Hard	Sliding Window	Soln 1
0481	Magical String	Free	48%	Medium		Soln 1
0482	License Key Formatting	Free	43%	Easy		Soln 1
0484	Find Permutation	Paid	64%	Medium		Soln 1
0485	Max Consecutive Ones	Free	53%	Easy	Array	Soln 1 Soln 2
0486	Predict the Winner	Free	48%	Medium	Dynamic Programming Minimax	Soln 1
0487	Max Consecutive Ones II	Paid	48%	Medium		Soln 1
0488	Zuma Game	Free	39%	Hard	Depth-first Search	Soln 1
0489	Robot Room Cleaner	Paid	72%	Hard		Soln 1 Soln 2
0490	The Maze	Paid	52%	Medium		Soln 1 Soln 2
0491	Increasing Subsequences	Free	47%	Medium	Depth-first Search	Soln 1
0492	Construct the Rectangle	Free	50%	Easy		Soln 1
0493	Reverse Pairs	Free	26%	Hard	Binary Search Divide and Conquer Sort Binary Indexed Tree Segment Tree	Soln 1 Soln 2 Soln 3
0494	Target Sum	Free	46%	Medium	Dynamic Programming Depth-first Search	Soln 1 Soln 2 Soln 3
0495	Teemo Attacking	Free	56%	Medium	Array	Soln 1
0496	Next Greater Element I	Free	65%	Easy	Stack	Soln 1 Soln 2 Soln 3
0497	Random Point in Non-overlapping Rectangles	Free	39%	Medium	Binary Search Random	Soln 1 Soln 2
0498	Diagonal Traverse	Free	49%	Medium		Soln 1 Soln 2
0500	Keyboard Row	Free	65%	Easy	Hash Table	Soln 1 Soln 2
0501	Find Mode in Binary Search Tree	Free	43%	Easy	Tree	Soln 1
0502	IPO	Free	41%	Hard	Heap Greedy	Soln 1 Soln 2
0503	Next Greater Element II	Free	58%	Medium	Stack	Soln 1
0504	Base 7	Free	46%	Easy		Soln 1 Soln 2
0506	Relative Ranks	Free	51%	Easy		Soln 1 Soln 2
0507	Perfect Number	Free	36%	Easy	Math	Soln 1
0508	Most Frequent Subtree Sum	Free	59%	Medium	Hash Table Tree	Soln 1
0509	Fibonacci Number	Free	67%	Easy	Array	Soln 1
0510	Inorder Successor in BST II	Paid	60%	Medium		Soln 1
0513	Find Bottom Left Tree Value	Free	62%	Medium	Tree Depth-first Search Breadth-first Search	Soln 1
0514	Freedom Trail	Free	45%	Hard	Divide and Conquer Dynamic Programming Depth-first Search	Soln 1
0515	Find Largest Value in Each Tree Row	Free	62%	Medium	Tree Depth-first Search Breadth-first Search	Soln 1 Soln 2
0516	Longest Palindromic Subsequence	Free	55%	Medium	Dynamic Programming	Soln 1 Soln 2
0517	Super Washing Machines	Free	38%	Hard	Math Dynamic Programming	Soln 1
0518	Coin Change 2	Free	51%	Medium		Soln 1
0519	Random Flip Matrix	Free	37%	Medium	Random	Soln 1
0520	Detect Capital	Free	54%	Easy	String	Soln 1
0521	Longest Uncommon Subsequence I	Free	58%	Easy	String	Soln 1
0523	Continuous Subarray Sum	Free	25%	Medium	Math Dynamic Programming	Soln 1
0524	Longest Word in Dictionary through Deleting	Free	49%	Medium	Two Pointers Sort	Soln 1 Soln 2 Soln 3
0525	Contiguous Array	Free	43%	Medium	Hash Table	Soln 1 Soln 2
0526	Beautiful Arrangement	Free	59%	Medium	Backtracking	Soln 1
0528	Random Pick with Weight	Free	44%	Medium	Binary Search Random	Soln 1 Soln 2
0529	Minesweeper	Free	60%	Medium	Depth-first Search Breadth-first Search	Soln 1
0530	Minimum Absolute Difference in BST	Free	54%	Easy	Tree	Soln 1 Soln 2
0531	Lonely Pixel I	Paid	59%	Medium		Soln 1 Soln 2
0532	K-diff Pairs in an Array	Free	35%	Medium	Array Two Pointers
0535	Encode and Decode TinyURL	Free	81%	Medium	Hash Table Math	Soln 1
0536	Construct Binary Tree from String	Paid	50%	Medium		Soln 1
0537	Complex Number Multiplication	Free	68%	Medium	Math String	Soln 1 Soln 2
0538	Convert BST to Greater Tree	Free	56%	Medium	Tree	Soln 1 Soln 2
0539	Minimum Time Difference	Free	52%	Medium	String	Soln 1
0540	Single Element in a Sorted Array	Free	58%	Medium		Soln 1 Soln 2
0541	Reverse String II	Free	49%	Easy	String	Soln 1
0542	01 Matrix	Free	40%	Medium	Depth-first Search Breadth-first Search	Soln 1
0543	Diameter of Binary Tree	Free	49%	Easy	Tree	Soln 1 Soln 2
0544	Output Contest Matches	Paid	76%	Medium		Soln 1
0547	Friend Circles	Free	60%	Medium	Depth-first Search Union Find	Soln 1 Soln 2
0549	Binary Tree Longest Consecutive Sequence II	Paid	47%	Medium		Soln 1
0551	Student Attendance Record I	Free	46%	Easy	String	Soln 1 Soln 2
0552	Student Attendance Record II	Free	37%	Hard	Dynamic Programming	Soln 1
0553	Optimal Division	Free	57%	Medium	Math String	Soln 1
0554	Brick Wall	Free	50%	Medium	Hash Table
0556	Next Greater Element III	Free	32%	Medium	String	Soln 1 Soln 2
0557	Reverse Words in a String III	Free	71%	Easy	String	Soln 1
0559	Maximum Depth of N-ary Tree	Free	69%	Easy	Tree Depth-first Search Breadth-first Search	Soln 1
0560	Subarray Sum Equals K	Free	44%	Medium	Array Hash Table	Soln 1 Soln 2
0561	Array Partition I	Free	73%	Easy	Array	Soln 1 Soln 2
0562	Longest Line of Consecutive One in Matrix	Paid	46%	Medium		Soln 1
0563	Binary Tree Tilt	Free	52%	Easy	Tree	Soln 1
0565	Array Nesting	Free	56%	Medium	Array	Soln 1
0566	Reshape the Matrix	Free	61%	Easy	Array	Soln 1
0567	Permutation in String	Free	44%	Medium	Two Pointers Sliding Window	Soln 1 Soln 2 Soln 3
0572	Subtree of Another Tree	Free	44%	Easy	Tree	Soln 1
0573	Squirrel Simulation	Paid	56%	Medium		Soln 1
0575	Distribute Candies	Free	62%	Easy	Hash Table	Soln 1
0581	Shortest Unsorted Continuous Subarray	Free	31%	Medium	Array	Soln 1
0582	Kill Process	Paid	62%	Medium		Soln 1
0583	Delete Operation for Two Strings	Free	49%	Medium	String	Soln 1 Soln 2
0589	N-ary Tree Preorder Traversal	Free	73%	Easy	Tree	Soln 1 Soln 2
0590	N-ary Tree Postorder Traversal	Free	73%	Easy	Tree	Soln 1 Soln 2
0593	Valid Square	Free	43%	Medium	Math	Soln 1 Soln 2
0594	Longest Harmonious Subsequence	Free	47%	Easy	Hash Table	Soln 1
0598	Range Addition II	Free	50%	Easy	Math	Soln 1
0599	Minimum Index Sum of Two Lists	Free	51%	Easy	Hash Table	Soln 1
0604	Design Compressed String Iterator	Paid	38%	Easy		Soln 1
0605	Can Place Flowers	Free	31%	Easy	Array	Soln 1
0606	Construct String from Binary Tree	Free	55%	Easy	String Tree	Soln 1
0609	Find Duplicate File in System	Free	61%	Medium	Hash Table String	Soln 1 Soln 2
0611	Valid Triangle Number	Free	49%	Medium	Array	Soln 1
0616	Add Bold Tag in String	Paid	44%	Medium		Soln 1 Soln 2
0617	Merge Two Binary Trees	Free	75%	Easy	Tree	Soln 1
0621	Task Scheduler	Free	51%	Medium	Array Greedy Queue	Soln 1 Soln 2
0623	Add One Row to Tree	Free	50%	Medium	Tree	Soln 1
0624	Maximum Distance in Arrays	Paid	39%	Medium		Soln 1
0625	Minimum Factorization	Paid	33%	Medium		Soln 1
0628	Maximum Product of Three Numbers	Free	47%	Easy	Array Math	Soln 1
0630	Course Schedule III	Free	34%	Hard	Greedy	Soln 1
0632	Smallest Range Covering Elements from K Lists	Free	54%	Hard	Hash Table Two Pointers String	Soln 1
0633	Sum of Square Numbers	Free	32%	Medium	Math	Soln 1
0634	Find the Derangement of An Array	Paid	40%	Medium		Soln 1
0636	Exclusive Time of Functions	Free	53%	Medium	Stack	Soln 1 Soln 2 Soln 3
0637	Average of Levels in Binary Tree	Free	64%	Easy	Tree	Soln 1
0638	Shopping Offers	Free	52%	Medium	Dynamic Programming Depth-first Search	Soln 1
0639	Decode Ways II	Free	27%	Hard	Dynamic Programming	Soln 1
0641	Design Circular Deque	Free	55%	Medium	Design Queue	Soln 1
0642	Design Search Autocomplete System	Paid	46%	Hard		Soln 1
0643	Maximum Average Subarray I	Free	42%	Easy	Array	Soln 1
0644	Maximum Average Subarray II	Paid	34%	Hard		Soln 1
0645	Set Mismatch	Free	42%	Easy	Hash Table Math	Soln 1 Soln 2
0646	Maximum Length of Pair Chain	Free	52%	Medium	Dynamic Programming	Soln 1
0647	Palindromic Substrings	Free	61%	Medium	String Dynamic Programming	Soln 1
0649	Dota2 Senate	Free	39%	Medium	Greedy	Soln 1
0650	2 Keys Keyboard	Free	50%	Medium	Dynamic Programming	Soln 1
0652	Find Duplicate Subtrees	Free	51%	Medium	Tree	Soln 1 Soln 2
0653	Two Sum IV - Input is a BST	Free	56%	Easy	Tree	Soln 1 Soln 2
0654	Maximum Binary Tree	Free	81%	Medium	Tree	Soln 1
0656	Coin Path	Paid	29%	Hard		Soln 1 Soln 2
0657	Robot Return to Origin	Free	73%	Easy	String	Soln 1 Soln 2 Soln 3
0658	Find K Closest Elements	Free	42%	Medium	Binary Search	Soln 1
0659	Split Array into Consecutive Subsequences	Free	44%	Medium	Heap Greedy	Soln 1 Soln 2 Soln 3
0660	Remove 9	Paid	54%	Hard		Soln 1
0661	Image Smoother	Free	52%	Easy	Array	Soln 1
0662	Maximum Width of Binary Tree	Free	40%	Medium	Tree	Soln 1
0663	Equal Tree Partition	Paid	40%	Medium		Soln 1
0665	Non-decreasing Array	Free	20%	Easy	Array	Soln 1
0666	Path Sum IV	Paid	55%	Medium		Soln 1
0668	Kth Smallest Number in Multiplication Table	Free	47%	Hard	Binary Search	Soln 1 Soln 2
0669	Trim a Binary Search Tree	Free	63%	Easy	Tree	Soln 1
0670	Maximum Swap	Free	45%	Medium	Array Math	Soln 1 Soln 2
0671	Second Minimum Node In a Binary Tree	Free	43%	Easy	Tree	Soln 1
0673	Number of Longest Increasing Subsequence	Free	38%	Medium	Dynamic Programming	Soln 1 Soln 2
0674	Longest Continuous Increasing Subsequence	Free	46%	Easy	Array	Soln 1 Soln 2
0675	Cut Off Trees for Golf Event	Free	35%	Hard	Breadth-first Search	Soln 1 Soln 2
0676	Implement Magic Dictionary	Free	55%	Medium	Hash Table Trie	Soln 1
0677	Map Sum Pairs	Free	54%	Medium	Trie	Soln 1 Soln 2
0678	Valid Parenthesis String	Free	31%	Medium	String	Soln 1
0679	24 Game	Free	47%	Hard	Depth-first Search	Soln 1
0680	Valid Palindrome II	Free	37%	Easy	String	Soln 1
0681	Next Closest Time	Paid	46%	Medium		Soln 1
0682	Baseball Game	Free	65%	Easy	Stack	Soln 1
0683	K Empty Slots	Paid	36%	Hard		Soln 1 Soln 2
0684	Redundant Connection	Free	58%	Medium	Tree Union Find Graph	Soln 1 Soln 2 Soln 3
0685	Redundant Connection II	Free	33%	Hard	Tree Depth-first Search Union Find Graph	Soln 1
0686	Repeated String Match	Free	33%	Medium	String	Soln 1
0687	Longest Univalue Path	Free	37%	Medium	Tree Recursion	Soln 1
0688	Knight Probability in Chessboard	Free	50%	Medium	Dynamic Programming	Soln 1
0689	Maximum Sum of 3 Non-Overlapping Subarrays	Free	47%	Hard	Array Dynamic Programming	Soln 1
0690	Employee Importance	Free	58%	Easy	Hash Table Depth-first Search Breadth-first Search	Soln 1 Soln 2
0691	Stickers to Spell Word	Free	44%	Hard	Dynamic Programming Backtracking	Soln 1
0692	Top K Frequent Words	Free	53%	Medium	Hash Table Heap Trie	Soln 1 Soln 2
0693	Binary Number with Alternating Bits	Free	60%	Easy	Bit Manipulation	Soln 1
0694	Number of Distinct Islands	Paid	57%	Medium		Soln 1
0695	Max Area of Island	Free	64%	Medium	Array Depth-first Search	Soln 1
0696	Count Binary Substrings	Free	57%	Easy	String	Soln 1
0697	Degree of an Array	Free	54%	Easy	Array	Soln 1 Soln 2
0698	Partition to K Equal Sum Subsets	Free	45%	Medium	Dynamic Programming Recursion	Soln 1
0699	Falling Squares	Free	42%	Hard	Segment Tree Ordered Map	Soln 1
0700	Search in a Binary Search Tree	Free	73%	Easy	Tree	Soln 1
0701	Insert into a Binary Search Tree	Free	76%	Medium	Tree	Soln 1
0702	Search in a Sorted Array of Unknown Size	Paid	68%	Medium		Soln 1 Soln 2
0703	Kth Largest Element in a Stream	Free	50%	Easy	Heap	Soln 1
0704	Binary Search	Free	54%	Easy	Binary Search	Soln 1
0705	Design HashSet	Free	64%	Easy	Hash Table Design	Soln 1
0706	Design HashMap	Free	62%	Easy	Hash Table Design	Soln 1
0708	Insert into a Sorted Circular Linked List	Paid	32%	Medium		Soln 1 Soln 2 Soln 3
0709	To Lower Case	Free	80%	Easy	String	Soln 1
0710	Random Pick with Blacklist	Free	33%	Hard	Hash Table Binary Search Sort Random	Soln 1 Soln 2
0711	Number of Distinct Islands II	Paid	49%	Hard		Soln 1
0712	Minimum ASCII Delete Sum for Two Strings	Free	59%	Medium	Dynamic Programming	Soln 1 Soln 2
0713	Subarray Product Less Than K	Free	40%	Medium	Array Two Pointers	Soln 1 Soln 2
0714	Best Time to Buy and Sell Stock with Transaction Fee	Free	56%	Medium	Array Dynamic Programming Greedy	Soln 1 Soln 2
0715	Range Module	Free	40%	Hard	Segment Tree Ordered Map	Soln 1 Soln 2
0716	Max Stack	Paid	43%	Easy		Soln 1
0717	1-bit and 2-bit Characters	Free	48%	Easy	Array	Soln 1 Soln 2 Soln 3
0718	Maximum Length of Repeated Subarray	Free	50%	Medium	Array Hash Table Binary Search Dynamic Programming	Soln 1
0719	Find K-th Smallest Pair Distance	Free	32%	Hard	Array Binary Search Heap	Soln 1 Soln 2
0720	Longest Word in Dictionary	Free	49%	Easy	Hash Table Trie	Soln 1
0722	Remove Comments	Free	36%	Medium	String	Soln 1 Soln 2
0723	Candy Crush	Paid	72%	Medium		Soln 1
0724	Find Pivot Index	Free	45%	Easy	Array	Soln 1
0725	Split Linked List in Parts	Free	53%	Medium	Linked List	Soln 1
0726	Number of Atoms	Free	51%	Hard	Hash Table Stack Recursion	Soln 1
0727	Minimum Window Subsequence	Paid	42%	Hard		Soln 1 Soln 2
0728	Self Dividing Numbers	Free	75%	Easy	Math	Soln 1
0729	My Calendar I	Free	53%	Medium	Array	Soln 1 Soln 2
0731	My Calendar II	Free	50%	Medium	Ordered Map	Soln 1 Soln 2 Soln 3 Soln 4
0732	My Calendar III	Free	61%	Hard	Segment Tree Ordered Map	Soln 1 Soln 2 Soln 3 Soln 4
0733	Flood Fill	Free	56%	Easy	Depth-first Search	Soln 1
0734	Sentence Similarity	Paid	42%	Easy		Soln 1
0735	Asteroid Collision	Free	43%	Medium	Stack	Soln 1
0737	Sentence Similarity II	Paid	46%	Medium		Soln 1 Soln 2 Soln 3
0738	Monotone Increasing Digits	Free	45%	Medium	Greedy	Soln 1 Soln 2
0739	Daily Temperatures	Free	64%	Medium	Hash Table Stack	Soln 1 Soln 2
0740	Delete and Earn	Free	49%	Medium	Dynamic Programming	Soln 1
0741	Cherry Pickup	Free	35%	Hard	Dynamic Programming	Soln 1 Soln 2
0742	Closest Leaf in a Binary Tree	Paid	44%	Medium		Soln 1
0743	Network Delay Time	Free	45%	Medium	Heap Depth-first Search Breadth-first Search Graph	Soln 1 Soln 2 Soln 3
0744	Find Smallest Letter Greater Than Target	Free	46%	Easy	Binary Search	Soln 1
0746	Min Cost Climbing Stairs	Free	51%	Easy	Array Dynamic Programming	Soln 1 Soln 2
0747	Largest Number At Least Twice of Others	Free	43%	Easy	Array	Soln 1 Soln 2
0748	Shortest Completing Word	Free	57%	Easy	Hash Table	Soln 1
0750	Number Of Corner Rectangles	Paid	67%	Medium		Soln 1 Soln 2
0752	Open the Lock	Free	52%	Medium	Breadth-first Search	Soln 1
0753	Cracking the Safe	Free	52%	Hard	Math Depth-first Search	Soln 1
0755	Pour Water	Paid	44%	Medium		Soln 1
0756	Pyramid Transition Matrix	Free	55%	Medium	Bit Manipulation Depth-first Search	Soln 1
0758	Bold Words in String	Paid	47%	Easy		Soln 1
0759	Employee Free Time	Paid	67%	Hard		Soln 1 Soln 2 Soln 3
0760	Find Anagram Mappings	Paid	82%	Easy		Soln 1
0761	Special Binary String	Free	59%	Hard	String Recursion	Soln 1
0762	Prime Number of Set Bits in Binary Representation	Free	64%	Easy	Bit Manipulation	Soln 1
0763	Partition Labels	Free	78%	Medium	Two Pointers Greedy	Soln 1 Soln 2
0764	Largest Plus Sign	Free	46%	Medium	Dynamic Programming	Soln 1
0765	Couples Holding Hands	Free	55%	Hard	Greedy Union Find Graph	Soln 1 Soln 2
0766	Toeplitz Matrix	Free	66%	Easy	Array	Soln 1
0767	Reorganize String	Free	50%	Medium	String Heap Greedy Sort	Soln 1 Soln 2
0768	Max Chunks To Make Sorted II	Free	50%	Hard	Array	Soln 1 Soln 2
0769	Max Chunks To Make Sorted	Free	55%	Medium	Array	Soln 1 Soln 2
0771	Jewels and Stones	Free	87%	Easy	Hash Table	Soln 1
0772	Basic Calculator III	Paid	43%	Hard		Soln 1 Soln 2
0774	Minimize Max Distance to Gas Station	Paid	48%	Hard		Soln 1 Soln 2
0775	Global and Local Inversions	Free	42%	Medium	Array Math	Soln 1
0776	Split BST	Paid	56%	Medium		Soln 1 Soln 2
0777	Swap Adjacent in LR String	Free	35%	Medium	Brainteaser	Soln 1 Soln 2
0778	Swim in Rising Water	Free	54%	Hard	Binary Search Heap Depth-first Search Union Find	Soln 1 Soln 2
0779	K-th Symbol in Grammar	Free	38%	Medium	Recursion	Soln 1
0781	Rabbits in Forest	Free	55%	Medium	Hash Table Math	Soln 1
0783	Minimum Distance Between BST Nodes	Free	53%	Easy	Tree Recursion	Soln 1 Soln 2
0784	Letter Case Permutation	Free	66%	Medium	Backtracking Bit Manipulation	Soln 1 Soln 2
0785	Is Graph Bipartite?	Free	48%	Medium	Depth-first Search Breadth-first Search Graph	Soln 1
0786	K-th Smallest Prime Fraction	Free	41%	Hard	Binary Search Heap	Soln 1 Soln 2
0787	Cheapest Flights Within K Stops	Free	39%	Medium	Dynamic Programming Heap Breadth-first Search	Soln 1 Soln 2
0788	Rotated Digits	Free	57%	Easy	String	Soln 1
0789	Escape The Ghosts	Free	58%	Medium	Math	Soln 1
0790	Domino and Tromino Tiling	Free	40%	Medium	Dynamic Programming	Soln 1
0791	Custom Sort String	Free	66%	Medium	String	Soln 1
0792	Number of Matching Subsequences	Free	48%	Medium	Array	Soln 1 Soln 2 Soln 3
0793	Preimage Size of Factorial Zeroes Function	Free	40%	Hard	Binary Search	Soln 1 Soln 2
0795	Number of Subarrays with Bounded Maximum	Free	47%	Medium	Array	Soln 1
0796	Rotate String	Free	49%	Easy		Soln 1 Soln 2
0797	All Paths From Source to Target	Free	78%	Medium		Soln 1 Soln 2
0799	Champagne Tower	Free	44%	Medium		Soln 1 Soln 2
0800	Similar RGB Color	Paid	62%	Easy		Soln 1
0801	Minimum Swaps To Make Sequences Increasing	Free	39%	Medium	Dynamic Programming	Soln 1 Soln 2
0802	Find Eventual Safe States	Free	49%	Medium	Depth-first Search Graph	Soln 1
0804	Unique Morse Code Words	Free	79%	Easy	String	Soln 1 Soln 2
0805	Split Array With Same Average	Free	27%	Hard	Math	Soln 1
0806	Number of Lines To Write String	Free	65%	Easy		Soln 1
0807	Max Increase to Keep City Skyline	Free	84%	Medium		Soln 1
0809	Expressive Words	Free	47%	Medium	String	Soln 1 Soln 2
0810	Chalkboard XOR Game	Free	49%	Hard	Math	Soln 1
0811	Subdomain Visit Count	Free	71%	Easy	Hash Table	Soln 1
0812	Largest Triangle Area	Free	59%	Easy	Math	Soln 1
0813	Largest Sum of Averages	Free	51%	Medium	Dynamic Programming	Soln 1 Soln 2
0814	Binary Tree Pruning	Free	73%	Medium	Tree	Soln 1
0815	Bus Routes	Free	43%	Hard	Breadth-first Search	Soln 1 Soln 2
0816	Ambiguous Coordinates	Free	48%	Medium	String	Soln 1
0817	Linked List Components	Free	57%	Medium	Linked List	Soln 1 Soln 2
0819	Most Common Word	Free	45%	Easy	String	Soln 1
0821	Shortest Distance to a Character	Free	68%	Easy		Soln 1 Soln 2
0822	Card Flipping Game	Free	43%	Medium		Soln 1
0823	Binary Trees With Factors	Free	36%	Medium		Soln 1 Soln 2
0824	Goat Latin	Free	66%	Easy	String	Soln 1
0826	Most Profit Assigning Work	Free	39%	Medium	Two Pointers	Soln 1 Soln 2
0828	Count Unique Characters of All Substrings of a Given String	Free	47%	Hard	Two Pointers	Soln 1
0829	Consecutive Numbers Sum	Free	39%	Hard	Math	Soln 1
0830	Positions of Large Groups	Free	50%	Easy	Array	Soln 1 Soln 2
0831	Masking Personal Information	Free	45%	Medium	String	Soln 1
0832	Flipping an Image	Free	78%	Easy	Array	Soln 1 Soln 2 Soln 3
0833	Find And Replace in String	Free	51%	Medium	String	Soln 1 Soln 2 Soln 3
0834	Sum of Distances in Tree	Free	45%	Hard	Tree Depth-first Search	Soln 1 Soln 2
0835	Image Overlap	Free	62%	Medium	Array	Soln 1 Soln 2
0836	Rectangle Overlap	Free	46%	Easy	Math	Soln 1
0837	New 21 Game	Free	35%	Medium	Dynamic Programming	Soln 1
0838	Push Dominoes	Free	49%	Medium	Two Pointers Dynamic Programming	Soln 1
0839	Similar String Groups	Free	39%	Hard	Depth-first Search Union Find Graph	Soln 1 Soln 2
0841	Keys and Rooms	Free	65%	Medium	Depth-first Search Graph	Soln 1 Soln 2 Soln 3
0842	Split Array into Fibonacci Sequence	Free	37%	Medium	String Backtracking Greedy	Soln 1
0843	Guess the Word	Free	46%	Hard	Minimax	Soln 1 Soln 2
0844	Backspace String Compare	Free	47%	Easy	Two Pointers Stack	Soln 1 Soln 2
0845	Longest Mountain in Array	Free	38%	Medium	Two Pointers	Soln 1
0846	Hand of Straights	Free	55%	Medium	Ordered Map	Soln 1 Soln 2
0847	Shortest Path Visiting All Nodes	Free	53%	Hard	Dynamic Programming Breadth-first Search	Soln 1 Soln 2
0848	Shifting Letters	Free	45%	Medium	String	Soln 1
0849	Maximize Distance to Closest Person	Free	44%	Medium	Array	Soln 1
0850	Rectangle Area II	Free	48%	Hard	Segment Tree Line Sweep	Soln 1
0851	Loud and Rich	Free	52%	Medium	Depth-first Search	Soln 1 Soln 2
0852	Peak Index in a Mountain Array	Free	72%	Easy	Binary Search	Soln 1
0853	Car Fleet	Free	43%	Medium	Sort	Soln 1 Soln 2
0855	Exam Room	Free	43%	Medium	Ordered Map	Soln 1 Soln 2
0856	Score of Parentheses	Free	62%	Medium	String Stack	Soln 1 Soln 2
0857	Minimum Cost to Hire K Workers	Free	50%	Hard	Heap	Soln 1 Soln 2
0858	Mirror Reflection	Free	59%	Medium	Math	Soln 1
0859	Buddy Strings	Free	30%	Easy	String	Soln 1
0860	Lemonade Change	Free	52%	Easy	Greedy	Soln 1 Soln 2
0861	Score After Flipping Matrix	Free	73%	Medium	Greedy	Soln 1 Soln 2
0862	Shortest Subarray with Sum at Least K	Free	25%	Hard	Binary Search Queue	Soln 1
0863	All Nodes Distance K in Binary Tree	Free	57%	Medium	Tree Depth-first Search Breadth-first Search	Soln 1
0865	Smallest Subtree with all the Deepest Nodes	Free	62%	Medium	Tree	Soln 1 Soln 2
0867	Transpose Matrix	Free	62%	Easy	Array	Soln 1
0868	Binary Gap	Free	61%	Easy	Math	Soln 1 Soln 2
0869	Reordered Power of 2	Free	54%	Medium	Math	Soln 1
0870	Advantage Shuffle	Free	46%	Medium	Array Greedy	Soln 1
0871	Minimum Number of Refueling Stops	Free	32%	Hard	Dynamic Programming Heap	Soln 1
0872	Leaf-Similar Trees	Free	65%	Easy	Tree Depth-first Search	Soln 1 Soln 2
0873	Length of Longest Fibonacci Subsequence	Free	48%	Medium	Array Dynamic Programming	Soln 1
0874	Walking Robot Simulation	Free	36%	Easy	Greedy	Soln 1
0875	Koko Eating Bananas	Free	53%	Medium	Binary Search	Soln 1 Soln 2
0876	Middle of the Linked List	Free	69%	Easy	Linked List	Soln 1
0877	Stone Game	Free	66%	Medium	Math Dynamic Programming Minimax	Soln 1
0878	Nth Magical Number	Free	29%	Hard	Math Binary Search	Soln 1 Soln 2
0880	Decoded String at Index	Free	25%	Medium	Stack	Soln 1
0881	Boats to Save People	Free	47%	Medium	Two Pointers Greedy	Soln 1
0882	Reachable Nodes In Subdivided Graph	Free	42%	Hard	Heap	Soln 1
0883	Projection Area of 3D Shapes	Free	68%	Easy	Math	Soln 1 Soln 2
0884	Uncommon Words from Two Sentences	Free	64%	Easy	Hash Table	Soln 1
0885	Spiral Matrix III	Free	70%	Medium	Math	Soln 1
0886	Possible Bipartition	Free	45%	Medium	Depth-first Search	Soln 1
0888	Fair Candy Swap	Free	59%	Easy	Array	Soln 1 Soln 2
0889	Construct Binary Tree from Preorder and Postorder Traversal	Free	67%	Medium	Tree	Soln 1 Soln 2
0890	Find and Replace Pattern	Free	74%	Medium	String	Soln 1 Soln 2
0892	Surface Area of 3D Shapes	Free	59%	Easy	Math Geometry	Soln 1
0893	Groups of Special-Equivalent Strings	Free	68%	Easy	String	Soln 1
0894	All Possible Full Binary Trees	Free	77%	Medium	Tree Recursion	Soln 1 Soln 2
0895	Maximum Frequency Stack	Free	62%	Hard	Hash Table Stack	Soln 1
0896	Monotonic Array	Free	58%	Easy	Array	Soln 1 Soln 2
0897	Increasing Order Search Tree	Free	74%	Easy	Tree Depth-first Search	Soln 1
0898	Bitwise ORs of Subarrays	Free	34%	Medium	Dynamic Programming Bit Manipulation	Soln 1
0899	Orderly Queue	Free	53%	Hard	Math String	Soln 1 Soln 2
0900	RLE Iterator	Free	55%	Medium	Array	Soln 1 Soln 2 Soln 3
0901	Online Stock Span	Free	61%	Medium	Stack	Soln 1 Soln 2 Soln 3
0902	Numbers At Most N Given Digit Set	Free	36%	Hard	Math Dynamic Programming	Soln 1 Soln 2
0904	Fruit Into Baskets	Free	43%	Medium	Two Pointers	Soln 1 Soln 2
0905	Sort Array By Parity	Free	75%	Easy	Array	Soln 1
0907	Sum of Subarray Minimums	Free	33%	Medium	Array Stack	Soln 1
0908	Smallest Range I	Free	66%	Easy	Math	Soln 1 Soln 2
0910	Smallest Range II	Free	27%	Medium	Math Greedy	Soln 1 Soln 2 Soln 3 Soln 4
0911	Online Election	Free	51%	Medium	Binary Search	Soln 1 Soln 2
0914	X of a Kind in a Deck of Cards	Free	34%	Easy	Array Math	Soln 1 Soln 2 Soln 3
0915	Partition Array into Disjoint Intervals	Free	46%	Medium	Array
0916	Word Subsets	Free	48%	Medium	String	Soln 1 Soln 2
0917	Reverse Only Letters	Free	58%	Easy	String	Soln 1 Soln 2
0918	Maximum Sum Circular Subarray	Free	34%	Medium	Array	Soln 1 Soln 2
0919	Complete Binary Tree Inserter	Free	58%	Medium	Tree	Soln 1 Soln 2
0921	Minimum Add to Make Parentheses Valid	Free	74%	Medium	Stack Greedy	Soln 1 Soln 2
0922	Sort Array By Parity II	Free	70%	Easy	Array Sort	Soln 1 Soln 2
0923	3Sum With Multiplicity	Free	36%	Medium	Two Pointers	Soln 1 Soln 2
0924	Minimize Malware Spread	Free	42%	Hard	Depth-first Search Union Find	Soln 1
0925	Long Pressed Name	Free	39%	Easy	Two Pointers String	Soln 1 Soln 2
0926	Flip String to Monotone Increasing	Free	53%	Medium	Array	Soln 1
0929	Unique Email Addresses	Free	67%	Easy	String	Soln 1 Soln 2
0930	Binary Subarrays With Sum	Free	44%	Medium	Hash Table Two Pointers	Soln 1 Soln 2
0931	Minimum Falling Path Sum	Free	63%	Medium	Dynamic Programming	Soln 1
0932	Beautiful Array	Free	61%	Medium	Divide and Conquer	Soln 1
0933	Number of Recent Calls	Free	72%	Easy	Queue	Soln 1 Soln 2 Soln 3
0934	Shortest Bridge	Free	49%	Medium	Depth-first Search Breadth-first Search	Soln 1 Soln 2
0936	Stamping The Sequence	Free	47%	Hard	String Greedy	Soln 1 Soln 2
0937	Reorder Data in Log Files	Free	54%	Easy	String	Soln 1
0938	Range Sum of BST	Free	83%	Easy	Tree Recursion	Soln 1
0939	Minimum Area Rectangle	Free	52%	Medium	Hash Table	Soln 1 Soln 2 Soln 3 Soln 4
0940	Distinct Subsequences II	Free	41%	Hard	Dynamic Programming	Soln 1 Soln 2
0941	Valid Mountain Array	Free	32%	Easy	Array	Soln 1 Soln 2 Soln 3
0942	DI String Match	Free	73%	Easy	Math	Soln 1
0943	Find the Shortest Superstring	Free	43%	Hard	Dynamic Programming	Soln 1
0944	Delete Columns to Make Sorted	Free	71%	Easy	Greedy	Soln 1
0945	Minimum Increment to Make Array Unique	Free	47%	Medium	Array	Soln 1 Soln 2
0946	Validate Stack Sequences	Free	63%	Medium	Stack	Soln 1
0947	Most Stones Removed with Same Row or Column	Free	55%	Medium	Depth-first Search Union Find	Soln 1 Soln 2
0948	Bag of Tokens	Free	46%	Medium	Greedy	Soln 1
0949	Largest Time for Given Digits	Free	36%	Medium	Math	Soln 1
0950	Reveal Cards In Increasing Order	Free	75%	Medium	Array	Soln 1 Soln 2
0951	Flip Equivalent Binary Trees	Free	66%	Medium	Tree	Soln 1 Soln 2 Soln 3
0952	Largest Component Size by Common Factor	Free	36%	Hard	Math Union Find	Soln 1 Soln 2 Soln 3 Soln 4
0953	Verifying an Alien Dictionary	Free	53%	Easy	Hash Table	Soln 1
0954	Array of Doubled Pairs	Free	35%	Medium	Array Hash Table	Soln 1
0955	Delete Columns to Make Sorted II	Free	33%	Medium	Greedy	Soln 1 Soln 2
0956	Tallest Billboard	Free	40%	Hard	Dynamic Programming	Soln 1 Soln 2
0957	Prison Cells After N Days	Free	40%	Medium	Hash Table	Soln 1
0958	Check Completeness of a Binary Tree	Free	52%	Medium	Tree	Soln 1
0959	Regions Cut By Slashes	Free	67%	Medium	Depth-first Search Union Find Graph	Soln 1
0961	N-Repeated Element in Size 2N Array	Free	74%	Easy	Hash Table	Soln 1 Soln 2
0962	Maximum Width Ramp	Free	46%	Medium	Array	Soln 1
0963	Minimum Area Rectangle II	Free	51%	Medium	Math Geometry	Soln 1 Soln 2
0965	Univalued Binary Tree	Free	68%	Easy	Tree	Soln 1 Soln 2
0967	Numbers With Same Consecutive Differences	Free	44%	Medium	Dynamic Programming	Soln 1
0968	Binary Tree Cameras	Free	38%	Hard	Dynamic Programming Tree Depth-first Search	Soln 1 Soln 2
0969	Pancake Sorting	Free	68%	Medium	Array Sort	Soln 1
0970	Powerful Integers	Free	40%	Easy	Hash Table Math	Soln 1
0973	K Closest Points to Origin	Free	64%	Medium	Divide and Conquer Heap Sort	Soln 1 Soln 2
0974	Subarray Sums Divisible by K	Free	50%	Medium	Array Hash Table	Soln 1
0975	Odd Even Jump	Free	42%	Hard	Dynamic Programming Stack Ordered Map	Soln 1
0976	Largest Perimeter Triangle	Free	58%	Easy	Math Sort	Soln 1 Soln 2
0977	Squares of a Sorted Array	Free	72%	Easy	Array Two Pointers	Soln 1
0978	Longest Turbulent Subarray	Free	47%	Medium	Array Dynamic Programming Sliding Window	Soln 1 Soln 2
0979	Distribute Coins in Binary Tree	Free	69%	Medium	Tree Depth-first Search	Soln 1
0980	Unique Paths III	Free	77%	Hard	Backtracking Depth-first Search	Soln 1
0981	Time Based Key-Value Store	Free	54%	Medium	Hash Table Binary Search	Soln 1 Soln 2 Soln 3
0982	Triples with Bitwise AND Equal To Zero	Free	56%	Hard	Dynamic Programming	Soln 1 Soln 2 Soln 3
0983	Minimum Cost For Tickets	Free	63%	Medium	Dynamic Programming	Soln 1 Soln 2
0984	String Without AAA or BBB	Free	38%	Medium	Greedy	Soln 1 Soln 2
0985	Sum of Even Numbers After Queries	Free	61%	Easy	Array	Soln 1 Soln 2
0986	Interval List Intersections	Free	68%	Medium	Two Pointers	Soln 1 Soln 2 Soln 3 Soln 4
0987	Vertical Order Traversal of a Binary Tree	Free	37%	Medium	Hash Table Tree	Soln 1 Soln 2 Soln 3
0988	Smallest String Starting From Leaf	Free	46%	Medium	Tree Depth-first Search	Soln 1 Soln 2
0989	Add to Array-Form of Integer	Free	45%	Easy	Array	Soln 1
0990	Satisfiability of Equality Equations	Free	46%	Medium	Union Find Graph	Soln 1 Soln 2
0991	Broken Calculator	Free	46%	Medium	Math Greedy	Soln 1
0992	Subarrays with K Different Integers	Free	50%	Hard	Hash Table Two Pointers Sliding Window	Soln 1
0993	Cousins in Binary Tree	Free	52%	Easy	Tree Breadth-first Search	Soln 1 Soln 2
0994	Rotting Oranges	Free	49%	Medium	Breadth-first Search	Soln 1 Soln 2
0995	Minimum Number of K Consecutive Bit Flips	Free	49%	Hard	Greedy Sliding Window	Soln 1 Soln 2 Soln 3
0996	Number of Squareful Arrays	Free	48%	Hard	Math Backtracking Graph	Soln 1
0997	Find the Town Judge	Free	50%	Easy	Graph	Soln 1
0998	Maximum Binary Tree II	Free	64%	Medium	Tree	Soln 1
0999	Available Captures for Rook	Free	67%	Easy	Array	Soln 1
1001	Grid Illumination	Free	36%	Hard	Hash Table	Soln 1
1002	Find Common Characters	Free	68%	Easy	Array Hash Table	Soln 1
1003	Check If Word Is Valid After Substitutions	Free	56%	Medium	String Stack	Soln 1
1004	Max Consecutive Ones III	Free	60%	Medium	Two Pointers Sliding Window	Soln 1
1005	Maximize Sum Of Array After K Negations	Free	52%	Easy	Greedy	Soln 1
1006	Clumsy Factorial	Free	54%	Medium	Math	Soln 1
1007	Minimum Domino Rotations For Equal Row	Free	51%	Medium	Array Greedy	Soln 1 Soln 2
1008	Construct Binary Search Tree from Preorder Traversal	Free	79%	Medium	Tree	Soln 1
1009	Complement of Base 10 Integer	Free	62%	Easy	Math	Soln 1
1010	Pairs of Songs With Total Durations Divisible by 60	Free	48%	Medium	Array	Soln 1
1011	Capacity To Ship Packages Within D Days	Free	59%	Medium	Array Binary Search	Soln 1 Soln 2
1012	Numbers With Repeated Digits	Free	38%	Hard	Math Dynamic Programming	Soln 1 Soln 2 Soln 3
1013	Partition Array Into Three Parts With Equal Sum	Free	50%	Easy	Array	Soln 1
1014	Best Sightseeing Pair	Free	53%	Medium	Array	Soln 1
1015	Smallest Integer Divisible by K	Free	42%	Medium	Math	Soln 1 Soln 2
1016	Binary String With Substrings Representing 1 To N	Free	59%	Medium	String	Soln 1
1017	Convert to Base -2	Free	59%	Medium	Math	Soln 1
1018	Binary Prefix Divisible By 5	Free	48%	Easy	Array	Soln 1 Soln 2
1019	Next Greater Node In Linked List	Free	58%	Medium	Linked List Stack	Soln 1 Soln 2
1020	Number of Enclaves	Free	59%	Medium	Depth-first Search	Soln 1
1021	Remove Outermost Parentheses	Free	79%	Easy	Stack	Soln 1
1022	Sum of Root To Leaf Binary Numbers	Free	71%	Easy	Tree	Soln 1
1023	Camelcase Matching	Free	57%	Medium	String Trie	Soln 1
1024	Video Stitching	Free	49%	Medium	Dynamic Programming	Soln 1
1025	Divisor Game	Free	66%	Easy	Math Dynamic Programming	Soln 1
1026	Maximum Difference Between Node and Ancestor	Free	69%	Medium	Tree Depth-first Search	Soln 1
1027	Longest Arithmetic Subsequence	Free	50%	Medium	Dynamic Programming	Soln 1 Soln 2 Soln 3
1028	Recover a Tree From Preorder Traversal	Free	70%	Hard	Tree Depth-first Search	Soln 1 Soln 2
1029	Two City Scheduling	Free	57%	Medium	Greedy	Soln 1
1030	Matrix Cells in Distance Order	Free	67%	Easy	Sort	Soln 1
1031	Maximum Sum of Two Non-Overlapping Subarrays	Free	59%	Medium	Array	Soln 1 Soln 2
1032	Stream of Characters	Free	48%	Hard	Trie	Soln 1 Soln 2 Soln 3
1033	Moving Stones Until Consecutive	Free	43%	Easy	Brainteaser	Soln 1
1034	Coloring A Border	Free	45%	Medium	Depth-first Search	Soln 1
1035	Uncrossed Lines	Free	56%	Medium	Array	Soln 1 Soln 2
1036	Escape a Large Maze	Free	35%	Hard	Breadth-first Search	Soln 1 Soln 2
1038	Binary Search Tree to Greater Sum Tree	Free	82%	Medium	Binary Search Tree	Soln 1
1041	Robot Bounded In Circle	Free	54%	Medium	Math	Soln 1 Soln 2
1042	Flower Planting With No Adjacent	Free	48%	Medium	Graph	Soln 1
1043	Partition Array for Maximum Sum	Free	66%	Medium	Graph	Soln 1
1044	Longest Duplicate Substring	Free	32%	Hard	Hash Table Binary Search	Soln 1
1046	Last Stone Weight	Free	62%	Easy	Heap Greedy	Soln 1
1047	Remove All Adjacent Duplicates In String	Free	70%	Easy	Stack	Soln 1 Soln 2
1048	Longest String Chain	Free	55%	Medium	Hash Table Dynamic Programming	Soln 1 Soln 2
1049	Last Stone Weight II	Free	44%	Medium	Dynamic Programming	Soln 1 Soln 2 Soln 3
1051	Height Checker	Free	72%	Easy	Array	Soln 1
1052	Grumpy Bookstore Owner	Free	55%	Medium	Array Sliding Window	Soln 1
1053	Previous Permutation With One Swap	Free	51%	Medium	Array Greedy	Soln 1
1054	Distant Barcodes	Free	44%	Medium	Heap Sort	Soln 1
1055	Shortest Way to Form String	Paid	57%	Medium		Soln 1
1056	Confusing Number	Paid	47%	Easy		Soln 1
1057	Campus Bikes	Paid	58%	Medium		Soln 1 Soln 2
1059	All Paths from Source Lead to Destination	Paid	43%	Medium		Soln 1
1060	Missing Element in Sorted Array	Paid	54%	Medium		Soln 1
1061	Lexicographically Smallest Equivalent String	Paid	66%	Medium		Soln 1
1062	Longest Repeating Substring	Paid	58%	Medium		Soln 1
1063	Number of Valid Subarrays	Paid	72%	Hard		Soln 1 Soln 2
1064	Fixed Point	Paid	66%	Easy		Soln 1
1065	Index Pairs of a String	Paid	61%	Easy		Soln 1
1066	Campus Bikes II	Paid	54%	Medium		Soln 1 Soln 2
1071	Greatest Common Divisor of Strings	Free	52%	Easy	String	Soln 1
1072	Flip Columns For Maximum Number of Equal Rows	Free	61%	Medium	Hash Table	Soln 1
1073	Adding Two Negabinary Numbers	Free	35%	Medium	Math	Soln 1
1074	Number of Submatrices That Sum to Target	Free	61%	Hard	Array Dynamic Programming Sliding Window	Soln 1 Soln 2
1078	Occurrences After Bigram	Free	65%	Easy	Hash Table	Soln 1
1079	Letter Tile Possibilities	Free	76%	Medium	Backtracking	Soln 1
1080	Insufficient Nodes in Root to Leaf Paths	Free	50%	Medium	Depth-first Search	Soln 1
1081	Smallest Subsequence of Distinct Characters	Free	53%	Medium	String	Soln 1
1085	Sum of Digits in the Minimum Number	Paid	75%	Easy		Soln 1
1086	High Five	Paid	79%	Easy		Soln 1
1087	Brace Expansion	Paid	63%	Medium		Soln 1 Soln 2
1088	Confusing Number II	Paid	45%	Hard		Soln 1 Soln 2
1089	Duplicate Zeros	Free	52%	Easy	Array	Soln 1
1090	Largest Values From Labels	Free	60%	Medium	Hash Table Greedy	Soln 1
1091	Shortest Path in Binary Matrix	Free	39%	Medium	Breadth-first Search	Soln 1 Soln 2
1092	Shortest Common Supersequence	Free	53%	Hard	Dynamic Programming	Soln 1 Soln 2 Soln 3
1093	Statistics from a Large Sample	Free	49%	Medium	Math Two Pointers	Soln 1
1095	Find in Mountain Array	Free	36%	Hard	Binary Search	Soln 1
1096	Brace Expansion II	Free	62%	Hard	String	Soln 1
1099	Two Sum Less Than K	Paid	61%	Easy		Soln 1
1100	Find K-Length Substrings With No Repeated Characters	Paid	73%	Medium		Soln 1
1101	The Earliest Moment When Everyone Become Friends	Paid	67%	Medium		Soln 1
1102	Path With Maximum Minimum Value	Paid	50%	Medium		Soln 1 Soln 2 Soln 3 Soln 4
1106	Parsing A Boolean Expression	Free	59%	Hard	String	Soln 1
1108	Defanging an IP Address	Free	88%	Easy	String	Soln 1
1109	Corporate Flight Bookings	Free	54%	Medium	Array Math	Soln 1 Soln 2
1110	Delete Nodes And Return Forest	Free	67%	Medium	Tree Depth-first Search	Soln 1 Soln 2
1111	Maximum Nesting Depth of Two Valid Parentheses Strings	Free	72%	Medium	Binary Search Greedy	Soln 1
1118	Number of Days in a Month	Paid	57%	Easy		Soln 1
1119	Remove Vowels from a String	Paid	90%	Easy		Soln 1
1120	Maximum Average Subtree	Paid	63%	Medium		Soln 1
1121	Divide Array Into Increasing Sequences	Paid	58%	Hard		Soln 1
1122	Relative Sort Array	Free	68%	Easy	Array Sort	Soln 1
1123	Lowest Common Ancestor of Deepest Leaves	Free	67%	Medium	Tree Depth-first Search	Soln 1
1124	Longest Well-Performing Interval	Free	33%	Medium	Stack	Soln 1
1125	Smallest Sufficient Team	Free	47%	Hard	Dynamic Programming Bit Manipulation	Soln 1 Soln 2
1133	Largest Unique Number	Paid	67%	Easy		Soln 1
1134	Armstrong Number	Paid	78%	Easy		Soln 1
1135	Connecting Cities With Minimum Cost	Paid	59%	Medium		Soln 1
1137	N-th Tribonacci Number	Free	56%	Easy	Recursion	Soln 1
1140	Stone Game II	Free	65%	Medium	Dynamic Programming	Soln 1
1143	Longest Common Subsequence	Free	59%	Medium	Dynamic Programming	Soln 1 Soln 2
1144	Decrease Elements To Make Array Zigzag	Free	46%	Medium	Array	Soln 1
1145	Binary Tree Coloring Game	Free	51%	Medium	Tree Depth-first Search	Soln 1 Soln 2
1146	Snapshot Array	Free	37%	Medium	Array	Soln 1 Soln 2 Soln 3
1147	Longest Chunked Palindrome Decomposition	Free	59%	Hard	Dynamic Programming Rolling Hash	Soln 1 Soln 2
1150	Check If a Number Is Majority Element in a Sorted Array	Paid	58%	Easy		Soln 1
1151	Minimum Swaps to Group All 1's Together	Paid	58%	Medium		Soln 1
1153	String Transforms Into Another String	Paid	36%	Hard		Soln 1
1155	Number of Dice Rolls With Target Sum	Free	48%	Medium	Dynamic Programming	Soln 1
1156	Swap For Longest Repeated Character Substring	Free	48%	Medium	String	Soln 1
1157	Online Majority Element In Subarray	Free	39%	Hard	Array Binary Search Segment Tree	Soln 1
1160	Find Words That Can Be Formed by Characters	Free	67%	Easy	Array Hash Table	Soln 1
1162	As Far from Land as Possible	Free	44%	Medium	Breadth-first Search Graph	Soln 1
1165	Single-Row Keyboard	Paid	85%	Easy		Soln 1
1166	Design File System	Paid	58%	Medium		Soln 1
1167	Minimum Cost to Connect Sticks	Paid	64%	Medium		Soln 1
1169	Invalid Transactions	Free	32%	Medium	Array String	Soln 1
1170	Compare Strings by Frequency of the Smallest Character	Free	59%	Easy	Array String	Soln 1
1171	Remove Zero Sum Consecutive Nodes from Linked List	Free	41%	Medium	Linked List	Soln 1
1172	Dinner Plate Stacks	Free	38%	Hard	Design	Soln 1
1176	Diet Plan Performance	Paid	54%	Easy		Soln 1
1177	Can Make Palindrome from Substring	Free	36%	Medium	Array String	Soln 1
1178	Number of Valid Words for Each Puzzle	Free	38%	Hard	Hash Table Bit Manipulation	Soln 1
1180	Count Substrings with Only One Distinct Letter	Paid	77%	Easy		Soln 1
1182	Shortest Distance to Target Color	Paid	53%	Medium		Soln 1
1183	Maximum Number of Ones	Paid	56%	Hard		Soln 1
1187	Make Array Strictly Increasing	Free	42%	Hard	Dynamic Programming	Soln 1
1190	Reverse Substrings Between Each Pair of Parentheses	Free	64%	Medium	Stack	Soln 1
1192	Critical Connections in a Network	Free	50%	Hard	Depth-first Search	Soln 1 Soln 2
1196	How Many Apples Can You Put into the Basket	Paid	68%	Easy		Soln 1
1197	Minimum Knight Moves	Paid	37%	Medium		Soln 1
1198	Find Smallest Common Element in All Rows	Paid	75%	Medium		Soln 1 Soln 2 Soln 3
1199	Minimum Time to Build Blocks	Paid	38%	Hard		Soln 1 Soln 2
1200	Minimum Absolute Difference	Free	67%	Easy	Array	Soln 1
1201	Ugly Number III	Free	26%	Medium	Math Binary Search	Soln 1
1202	Smallest String With Swaps	Free	48%	Medium	Array Union Find	Soln 1
1203	Sort Items by Groups Respecting Dependencies	Free	49%	Hard	Depth-first Search Graph Topological Sort	Soln 1
1207	Unique Number of Occurrences	Free	72%	Easy	Hash Table	Soln 1
1209	Remove All Adjacent Duplicates in String II	Free	57%	Medium	Stack	Soln 1
1213	Intersection of Three Sorted Arrays	Paid	79%	Easy		Soln 1
1214	Two Sum BSTs	Paid	68%	Medium		Soln 1
1215	Stepping Numbers	Paid	43%	Medium		Soln 1
1217	Minimum Cost to Move Chips to The Same Position	Free	71%	Easy	Array Math Greedy	Soln 1
1218	Longest Arithmetic Subsequence of Given Difference	Free	46%	Medium	Math Dynamic Programming	Soln 1
1219	Path with Maximum Gold	Free	65%	Medium	Backtracking	Soln 1
1220	Count Vowels Permutation	Free	54%	Hard	Dynamic Programming	Soln 1
1221	Split a String in Balanced Strings	Free	84%	Easy	String Greedy	Soln 1
1222	Queens That Can Attack the King	Free	69%	Medium	Array	Soln 1
1223	Dice Roll Simulation	Free	47%	Medium	Dynamic Programming	Soln 1
1224	Maximum Equal Frequency	Free	34%	Hard	Hash Table	Soln 1
1228	Missing Number In Arithmetic Progression	Paid	52%	Easy		Soln 1
1229	Meeting Scheduler	Paid	54%	Medium		Soln 1
1230	Toss Strange Coins	Paid	49%	Medium		Soln 1
1232	Check If It Is a Straight Line	Free	44%	Easy	Array Math Geometry	Soln 1
1233	Remove Sub-Folders from the Filesystem	Free	61%	Medium	Array String	Soln 1 Soln 2
1234	Replace the Substring for Balanced String	Free	34%	Medium	Two Pointers String	Soln 1
1236	Web Crawler	Paid	64%	Medium		Soln 1
1238	Circular Permutation in Binary Representation	Free	66%	Medium	Math	Soln 1
1239	Maximum Length of a Concatenated String with Unique Characters	Free	49%	Medium	Backtracking Bit Manipulation	Soln 1
1243	Array Transformation	Paid	51%	Easy		Soln 1 Soln 2
1244	Design A Leaderboard	Paid	65%	Medium		Soln 1
1245	Tree Diameter	Paid	61%	Medium		Soln 1 Soln 2 Soln 3
1246	Palindrome Removal	Paid	46%	Hard		Soln 1
1252	Cells with Odd Values in a Matrix	Free	78%	Easy	Array	Soln 1
1254	Number of Closed Islands	Free	61%	Medium	Depth-first Search	Soln 1
1256	Encode Number	Paid	67%	Medium		Soln 1 Soln 2
1257	Smallest Common Region	Paid	60%	Medium		Soln 1
1258	Synonymous Sentences	Paid	67%	Medium		Soln 1
1259	Handshakes That Don't Cross	Paid	54%	Hard		Soln 1 Soln 2
1260	Shift 2D Grid	Free	62%	Easy	Array	Soln 1
1265	Print Immutable Linked List in Reverse	Paid	95%	Medium		Soln 1
1271	Hexspeak	Paid	55%	Easy		Soln 1
1272	Remove Interval	Paid	58%	Medium		Soln 1
1273	Delete Tree Nodes	Paid	63%	Medium		Soln 1
1275	Find Winner on a Tic Tac Toe Game	Free	53%	Easy	Array	Soln 1
1277	Count Square Submatrices with All Ones	Free	73%	Medium	Array Dynamic Programming	Soln 1
1287	Element Appearing More Than 25% In Sorted Array	Free	60%	Easy	Array	Soln 1
1288	Remove Covered Intervals	Free	57%	Medium	Line Sweep	Soln 1
1289	Minimum Falling Path Sum II	Free	62%	Hard	Dynamic Programming	Soln 1
1291	Sequential Digits	Free	57%	Medium	Backtracking	Soln 1
1299	Replace Elements with Greatest Element on Right Side	Free	74%	Easy	Array	Soln 1
1300	Sum of Mutated Array Closest to Target	Free	43%	Medium	Array Binary Search	Soln 1
1301	Number of Paths with Max Score	Free	38%	Hard	Dynamic Programming	Soln 1
1302	Deepest Leaves Sum	Free	84%	Medium	Tree Depth-first Search	Soln 1
1304	Find N Unique Integers Sum up to Zero	Free	76%	Easy	Array	Soln 1
1305	All Elements in Two Binary Search Trees	Free	78%	Medium	Sort Tree	Soln 1
1306	Jump Game III	Free	63%	Medium	Breadth-first Search Graph	Soln 1
1309	Decrypt String from Alphabet to Integer Mapping	Free	77%	Easy	String	Soln 1
1310	XOR Queries of a Subarray	Free	69%	Medium	Bit Manipulation	Soln 1 Soln 2
1311	Get Watched Videos by Your Friends	Free	44%	Medium	Hash Table String Breadth-first Search	Soln 1
1312	Minimum Insertion Steps to Make a String Palindrome	Free	59%	Hard	Dynamic Programming	Soln 1
1313	Decompress Run-Length Encoded List	Free	85%	Easy	Array	Soln 1
1314	Matrix Block Sum	Free	74%	Medium	Dynamic Programming	Soln 1
1315	Sum of Nodes with Even-Valued Grandparent	Free	84%	Medium	Tree Depth-first Search	Soln 1
1316	Distinct Echo Substrings	Free	49%	Hard	String Rolling Hash	Soln 1
1317	Convert Integer to the Sum of Two No-Zero Integers	Free	57%	Easy	Math	Soln 1
1318	Minimum Flips to Make a OR b Equal to c	Free	63%	Medium	Bit Manipulation	Soln 1
1319	Number of Operations to Make Network Connected	Free	55%	Medium	Depth-first Search Breadth-first Search Union Find	Soln 1
1320	Minimum Distance to Type a Word Using Two Fingers	Free	63%	Hard	Dynamic Programming	Soln 1
1323	Maximum 69 Number	Free	78%	Easy	Math	Soln 1
1324	Print Words Vertically	Free	59%	Medium	String	Soln 1 Soln 2
1325	Delete Leaves With a Given Value	Free	73%	Medium	Tree	Soln 1
1326	Minimum Number of Taps to Open to Water a Garden	Free	46%	Hard	Dynamic Programming Greedy	Soln 1
1328	Break a Palindrome	Free	45%	Medium	String	Soln 1
1329	Sort the Matrix Diagonally	Free	79%	Medium	Array Sort	Soln 1
1331	Rank Transform of an Array	Free	58%	Easy	Array	Soln 1
1332	Remove Palindromic Subsequences	Free	63%	Easy	String	Soln 1
1333	Filter Restaurants by Vegan-Friendly, Price and Distance	Free	57%	Medium	Array Sort	Soln 1
1334	Find the City With the Smallest Number of Neighbors at a Threshold Distance	Free	46%	Medium	Graph	Soln 1
1335	Minimum Difficulty of a Job Schedule	Free	58%	Hard	Dynamic Programming	Soln 1
1337	The K Weakest Rows in a Matrix	Free	70%	Easy	Array Binary Search	Soln 1
1342	Number of Steps to Reduce a Number to Zero	Free	86%	Easy	Bit Manipulation	Soln 1
1346	Check If N and Its Double Exist	Free	37%	Easy	Array	Soln 1
1351	Count Negative Numbers in a Sorted Matrix	Free	76%	Easy	Array Binary Search	Soln 1
1356	Sort Integers by The Number of 1 Bits	Free	69%	Easy	Sort Bit Manipulation	Soln 1
1357	Apply Discount Every n Orders	Free	66%	Medium	Design	Soln 1
1358	Number of Substrings Containing All Three Characters	Free	60%	Medium	String	Soln 1
1359	Count All Valid Pickup and Delivery Options	Free	57%	Hard	Math Dynamic Programming	Soln 1 Soln 2
1363	Largest Multiple of Three	Free	34%	Hard	Math Dynamic Programming	Soln 1
1365	How Many Numbers Are Smaller Than the Current Number	Free	86%	Easy	Array Hash Table	Soln 1
1366	Rank Teams by Votes	Free	55%	Medium	Array Sort	Soln 1
1367	Linked List in Binary Tree	Free	41%	Medium	Linked List Dynamic Programming Tree	Soln 1
1368	Minimum Cost to Make at Least One Valid Path in a Grid	Free	56%	Hard	Breadth-first Search	Soln 1
1370	Increasing Decreasing String	Free	76%	Easy	String Sort	Soln 1
1373	Maximum Sum BST in Binary Tree	Free	38%	Hard	Dynamic Programming Binary Search Tree	Soln 1
1374	Generate a String With Characters That Have Odd Counts	Free	76%	Easy	String	Soln 1
1375	Bulb Switcher III	Free	64%	Medium	Array	Soln 1
1376	Time Needed to Inform All Employees	Free	56%	Medium	Depth-first Search	Soln 1 Soln 2
1377	Frog Position After T Seconds	Free	34%	Hard	Depth-first Search	Soln 1
1385	Find the Distance Value Between Two Arrays	Free	67%	Easy	Array
1387	Sort Integers by The Power Value	Free	71%	Medium	Sort Graph	Soln 1 Soln 2
1391	Check if There is a Valid Path in a Grid	Free	45%	Medium	Depth-first Search Breadth-first Search	Soln 1
1392	Longest Happy Prefix	Free	41%	Hard	String	Soln 1
1394	Find Lucky Integer in an Array	Free	63%	Easy	Array	Soln 1 Soln 2
1395	Count Number of Teams	Free	82%	Medium	Array	Soln 1
1396	Design Underground System	Free	68%	Medium	Design	Soln 1
1399	Count Largest Group	Free	65%	Easy	Array	Soln 1
1401	Circle and Rectangle Overlapping	Free	42%	Medium	Geometry	Soln 1
1403	Minimum Subsequence in Non-Increasing Order	Free	71%	Easy	Greedy Sort	Soln 1
1404	Number of Steps to Reduce a Number in Binary Representation to One	Free	50%	Medium	String Bit Manipulation	Soln 1
1413	Minimum Value to Get Positive Step by Step Sum	Free	65%	Easy	Array	Soln 1
1414	Find the Minimum Number of Fibonacci Numbers Whose Sum Is K	Free	64%	Medium	Array Greedy	Soln 1
1415	The k-th Lexicographical String of All Happy Strings of Length n	Free	70%	Medium	Backtracking	Soln 1
1416	Restore The Array	Free	36%	Hard	Dynamic Programming	Soln 1
1417	Reformat The String	Free	55%	Easy	String	Soln 1
1422	Maximum Score After Splitting a String	Free	56%	Easy	String	Soln 1
1423	Maximum Points You Can Obtain from Cards	Free	46%	Medium	Array Dynamic Programming Sliding Window	Soln 1
1424	Diagonal Traverse II	Free	45%	Medium	Array Sort	Soln 1
1425	Constrained Subsequence Sum	Free	45%	Hard	Dynamic Programming	Soln 1
1426	Counting Elements	Paid	59%	Easy		Soln 1
1427	Perform String Shifts	Paid	53%	Easy		Soln 1
1428	Leftmost Column with at Least a One	Paid	48%	Medium		Soln 1
1429	First Unique Number	Paid	49%	Medium		Soln 1
1430	Check If a String Is a Valid Sequence from Root to Leaves Path in a Binary Tree	Paid	45%	Medium		Soln 1 Soln 2
1431	Kids With the Greatest Number of Candies	Free	89%	Easy	Array	Soln 1
1433	Check If a String Can Break Another String	Free	67%	Medium	String Greedy	Soln 1
1434	Number of Ways to Wear Different Hats to Each Other	Free	39%	Hard	Dynamic Programming Bit Manipulation	Soln 1
1436	Destination City	Free	77%	Easy	String	Soln 1
1437	Check If All 1's Are at Least Length K Places Away	Free	62%	Medium	Array	Soln 1
1438	Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit	Free	44%	Medium	Array Sliding Window	Soln 1
1439	Find the Kth Smallest Sum of a Matrix With Sorted Rows	Free	60%	Hard	Heap	Soln 1
1441	Build an Array With Stack Operations	Free	69%	Easy	Stack	Soln 1
1442	Count Triplets That Can Form Two Arrays of Equal XOR	Free	71%	Medium	Array Math Bit Manipulation	Soln 1
1443	Minimum Time to Collect All Apples in a Tree	Free	55%	Medium	Tree Depth-first Search	Soln 1
1446	Consecutive Characters	Free	61%	Easy	String	Soln 1
1447	Simplified Fractions	Free	62%	Medium	Math	Soln 1
1448	Count Good Nodes in Binary Tree	Free	70%	Medium	Tree Depth-first Search	Soln 1
1449	Form Largest Integer With Digits That Add up to Target	Free	43%	Hard	String Dynamic Programming	Soln 1
1450	Number of Students Doing Homework at a Given Time	Free	77%	Easy	Array	Soln 1
1455	Check If a Word Occurs As a Prefix of Any Word in a Sentence	Free	65%	Easy	String	Soln 1
1456	Maximum Number of Vowels in a Substring of Given Length	Free	54%	Medium	String Sliding Window	Soln 1
1457	Pseudo-Palindromic Paths in a Binary Tree	Free	68%	Medium	Bit Manipulation Tree Depth-first Search	Soln 1
1458	Max Dot Product of Two Subsequences	Free	43%	Hard	Dynamic Programming	Soln 1
1460	Make Two Arrays Equal by Reversing Sub-arrays	Free	72%	Easy	Array	Soln 1
1461	Check If a String Contains All Binary Codes of Size K	Free	46%	Medium	String Bit Manipulation	Soln 1
1462	Course Schedule IV	Free	44%	Medium	Graph	Soln 1
1463	Cherry Pickup II	Free	66%	Hard	Dynamic Programming	Soln 1
1464	Maximum Product of Two Elements in an Array	Free	77%	Easy	Array	Soln 1
1465	Maximum Area of a Piece of Cake After Horizontal and Vertical Cuts	Free	31%	Medium	Array	Soln 1
1469	Find All The Lonely Nodes	Paid	81%	Easy
1470	Shuffle the Array	Free	89%	Easy		Soln 1 Soln 2 Soln 3
1471	The k Strongest Values in an Array	Free	58%	Medium		Soln 1 Soln 2 Soln 3
1472	Design Browser History	Free	69%	Medium		Soln 1
1474	Delete N Nodes After M Nodes of a Linked List	Paid	75%	Easy		Soln 1
1475	Final Prices With a Special Discount in a Shop	Free	75%	Easy		Soln 1
1476	Subrectangle Queries	Free	89%	Medium		Soln 1
1477	Find Two Non-overlapping Sub-arrays Each With Target Sum	Free	34%	Medium		Soln 1
1478	Allocate Mailboxes	Free	55%	Hard		Soln 1
1480	Running Sum of 1d Array	Free	90%	Easy		Soln 1
1481	Least Number of Unique Integers after K Removals	Free	55%	Medium		Soln 1
1482	Minimum Number of Days to Make m Bouquets	Free	49%	Medium		Soln 1
1483	Kth Ancestor of a Tree Node	Free	30%	Hard		Soln 1
1485	Clone Binary Tree With Random Pointer	Paid	80%	Medium		Soln 1
1486	XOR Operation in an Array	Free	84%	Easy		Soln 1
1487	Making File Names Unique	Free	30%	Medium		Soln 1
1488	Avoid Flood in The City	Free	25%	Medium		Soln 1
1490	Clone N-ary Tree	Paid	84%	Medium		Soln 1
1491	Average Salary Excluding the Minimum and Maximum Salary	Free	69%	Easy		Soln 1
1492	The kth Factor of n	Free	65%	Medium		Soln 1 Soln 2
1493	Longest Subarray of 1's After Deleting One Element	Free	59%	Medium		Soln 1
1494	Parallel Courses II	Free	31%	Hard		Soln 1
1496	Path Crossing	Free	56%	Easy		Soln 1
1497	Check If Array Pairs Are Divisible by k	Free	40%	Medium		Soln 1
1498	Number of Subsequences That Satisfy the Given Sum Condition	Free	38%	Medium		Soln 1
1500	Design a File Sharing System	Paid	46%	Medium		Soln 1
1502	Can Make Arithmetic Progression From Sequence	Free	71%	Easy		Soln 1
1503	Last Moment Before All Ants Fall Out of a Plank	Free	53%	Medium		Soln 1
1504	Count Submatrices With All Ones	Free	61%	Medium		Soln 1
1505	Minimum Possible Integer After at Most K Adjacent Swaps On Digits	Free	36%	Hard		Soln 1
1506	Find Root of N-Ary Tree	Paid	81%	Medium		Soln 1
1507	Reformat Date	Free	60%	Easy		Soln 1
1508	Range Sum of Sorted Subarray Sums	Free	63%	Medium		Soln 1
1509	Minimum Difference Between Largest and Smallest Value in Three Moves	Free	52%	Medium		Soln 1
1510	Stone Game IV	Free	59%	Hard		Soln 1
1512	Number of Good Pairs	Free	88%	Easy		Soln 1
1513	Number of Substrings With Only 1s	Free	41%	Medium		Soln 1
1514	Path with Maximum Probability	Free	39%	Medium		Soln 1
1515	Best Position for a Service Centre	Free	37%	Hard		Soln 1
1518	Water Bottles	Free	61%	Easy		Soln 1
1519	Number of Nodes in the Sub-Tree With the Same Label	Free	36%	Medium		Soln 1
1520	Maximum Number of Non-Overlapping Substrings	Free	35%	Hard		Soln 1
1521	Find a Value of a Mysterious Function Closest to Target	Free	44%	Hard		Soln 1 Soln 2
1523	Count Odd Numbers in an Interval Range	Free	55%	Easy		Soln 1
1524	Number of Sub-arrays With Odd Sum	Free	39%	Medium		Soln 1
1525	Number of Good Ways to Split a String	Free	67%	Medium		Soln 1 Soln 2
1526	Minimum Number of Increments on Subarrays to Form a Target Array	Free	59%	Hard		Soln 1
1528	Shuffle String	Free	86%	Easy		Soln 1
1529	Bulb Switcher IV	Free	71%	Medium		Soln 1
1530	Number of Good Leaf Nodes Pairs	Free	55%	Medium		Soln 1
1531	String Compression II	Free	33%	Hard		Soln 1
1533	Find the Index of the Large Integer	Paid	55%	Medium		Soln 1
1534	Count Good Triplets	Free	80%	Easy		Soln 1
1535	Find the Winner of an Array Game	Free	47%	Medium		Soln 1
1536	Minimum Swaps to Arrange a Binary Grid	Free	43%	Medium		Soln 1
1537	Get the Maximum Score	Free	36%	Hard		Soln 1
1538	Guess the Majority in a Hidden Array	Paid	61%	Medium		Soln 1
1539	Kth Missing Positive Number	Free	53%	Easy		Soln 1
1540	Can Convert String in K Moves	Free	30%	Medium		Soln 1
1541	Minimum Insertions to Balance a Parentheses String	Free	42%	Medium		Soln 1
1542	Find Longest Awesome Substring	Free	36%	Hard		Soln 1
1544	Make The String Great	Free	55%	Easy		Soln 1
1545	Find Kth Bit in Nth Binary String	Free	57%	Medium		Soln 1
1546	Maximum Number of Non-Overlapping Subarrays With Sum Equals Target	Free	44%	Medium		Soln 1
1547	Minimum Cost to Cut a Stick	Free	51%	Hard		Soln 1
1550	Three Consecutive Odds	Free	66%	Easy		Soln 1
1551	Minimum Operations to Make Array Equal	Free	78%	Medium		Soln 1
1552	Magnetic Force Between Two Balls	Free	48%	Medium		Soln 1
1553	Minimum Number of Days to Eat N Oranges	Free	29%	Hard		Soln 1
1556	Thousand Separator	Free	59%	Easy		Soln 1
1557	Minimum Number of Vertices to Reach All Nodes	Free	74%	Medium		Soln 1
1558	Minimum Numbers of Function Calls to Make Target Array	Free	63%	Medium		Soln 1
1562	Find Latest Group of Size M	Free	39%	Medium		Soln 1