diff --git a/Algorithms/Greedy Algorithm/Huffman Coding Algorithm/readme.md b/Algorithms/Greedy Algorithm/Huffman Coding Algorithm/readme.md index 7244a568..26f9d139 100644 --- a/Algorithms/Greedy Algorithm/Huffman Coding Algorithm/readme.md +++ b/Algorithms/Greedy Algorithm/Huffman Coding Algorithm/readme.md @@ -45,154 +45,119 @@ The time complexity for encoding each unique character based on its frequency is Extracting minimum frequency from the priority queue takes place 2*(n-1) times and its complexity is O(log n). Thus the overall complexity is O(nlog n). ## Implementations -* [C++](#cpp) * [C](#c) +* [C++](#cpp) * [Java](#java) * [Python](#python) -### CPP -```cpp -// Huffman Coding in C++ - -#include -using namespace std; - +### C +``` +#include +#include #define MAX_TREE_HT 50 +// Print the array +void printArray(int arr[], int n) { + int i; + for (i = 0; i < n; ++i) + printf("%d", arr[i]); + printf("\n"); +} + struct MinHNode { - unsigned freq; char item; + unsigned freq; struct MinHNode *left, *right; }; - -struct MinH { +struct MinHeap { unsigned size; unsigned capacity; struct MinHNode **array; }; - -// Creating Huffman tree node +// Create nodes struct MinHNode *newNode(char item, unsigned freq) { struct MinHNode *temp = (struct MinHNode *)malloc(sizeof(struct MinHNode)); - temp->left = temp->right = NULL; temp->item = item; temp->freq = freq; - return temp; } - -// Create min heap using given capacity -struct MinH *createMinH(unsigned capacity) { - struct MinH *minHeap = (struct MinH *)malloc(sizeof(struct MinH)); +// Create min heap +struct MinHeap *createMinH(unsigned capacity) { + struct MinHeap *minHeap = (struct MinHeap *)malloc(sizeof(struct MinHeap)); minHeap->size = 0; minHeap->capacity = capacity; minHeap->array = (struct MinHNode **)malloc(minHeap->capacity * sizeof(struct MinHNode *)); return minHeap; } - -// Print the array -void printArray(int arr[], int n) { - int i; - for (i = 0; i < n; ++i) - cout << arr[i]; - - cout << "\n"; -} - -// Swap function +// Function to swap void swapMinHNode(struct MinHNode **a, struct MinHNode **b) { struct MinHNode *t = *a; *a = *b; *b = t; } - // Heapify -void minHeapify(struct MinH *minHeap, int idx) { +void minHeapify(struct MinHeap *minHeap, int idx) { int smallest = idx; int left = 2 * idx + 1; int right = 2 * idx + 2; - if (left < minHeap->size && minHeap->array[left]->freq < minHeap->array[smallest]->freq) smallest = left; - if (right < minHeap->size && minHeap->array[right]->freq < minHeap->array[smallest]->freq) smallest = right; - if (smallest != idx) { - swapMinHNode(&minHeap->array[smallest], - &minHeap->array[idx]); + swapMinHNode(&minHeap->array[smallest], &minHeap->array[idx]); minHeapify(minHeap, smallest); } } - // Check if size if 1 -int checkSizeOne(struct MinH *minHeap) { +int checkSizeOne(struct MinHeap *minHeap) { return (minHeap->size == 1); } - -// Extract the min -struct MinHNode *extractMin(struct MinH *minHeap) { +// Extract min +struct MinHNode *extractMin(struct MinHeap *minHeap) { struct MinHNode *temp = minHeap->array[0]; minHeap->array[0] = minHeap->array[minHeap->size - 1]; - --minHeap->size; minHeapify(minHeap, 0); - return temp; } - -// Insertion -void insertMinHeap(struct MinH *minHeap, struct MinHNode *minHeapNode) { +// Insertion function +void insertMinHeap(struct MinHeap *minHeap, struct MinHNode *minHeapNode) { ++minHeap->size; int i = minHeap->size - 1; - while (i && minHeapNode->freq < minHeap->array[(i - 1) / 2]->freq) { minHeap->array[i] = minHeap->array[(i - 1) / 2]; i = (i - 1) / 2; } - minHeap->array[i] = minHeapNode; } - -// BUild min heap -void buildMinHeap(struct MinH *minHeap) { +void buildMinHeap(struct MinHeap *minHeap) { int n = minHeap->size - 1; int i; - for (i = (n - 1) / 2; i >= 0; --i) minHeapify(minHeap, i); } - int isLeaf(struct MinHNode *root) { return !(root->left) && !(root->right); } - -struct MinH *createAndBuildMinHeap(char item[], int freq[], int size) { - struct MinH *minHeap = createMinH(size); - +struct MinHeap *createAndBuildMinHeap(char item[], int freq[], int size) { + struct MinHeap *minHeap = createMinH(size); for (int i = 0; i < size; ++i) minHeap->array[i] = newNode(item[i], freq[i]); - minHeap->size = size; buildMinHeap(minHeap); - return minHeap; } - -struct MinHNode *buildHfTree(char item[], int freq[], int size) { +struct MinHNode *buildHuffmanTree(char item[], int freq[], int size) { struct MinHNode *left, *right, *top; - struct MinH *minHeap = createAndBuildMinHeap(item, freq, size); - + struct MinHeap *minHeap = createAndBuildMinHeap(item, freq, size); while (!checkSizeOne(minHeap)) { left = extractMin(minHeap); right = extractMin(minHeap); - top = newNode('$', left->freq + right->freq); - top->left = left; top->right = right; - insertMinHeap(minHeap, top); } return extractMin(minHeap); @@ -202,60 +167,55 @@ void printHCodes(struct MinHNode *root, int arr[], int top) { arr[top] = 0; printHCodes(root->left, arr, top + 1); } - if (root->right) { arr[top] = 1; printHCodes(root->right, arr, top + 1); } if (isLeaf(root)) { - cout << root->item << " | "; + printf(" %c | ", root->item); printArray(arr, top); } } - // Wrapper function void HuffmanCodes(char item[], int freq[], int size) { - struct MinHNode *root = buildHfTree(item, freq, size); - + struct MinHNode *root = buildHuffmanTree(item, freq, size); int arr[MAX_TREE_HT], top = 0; - printHCodes(root, arr, top); } + int main() { char arr[] = {'A', 'B', 'C', 'D'}; int freq[] = {5, 1, 6, 3}; - int size = sizeof(arr) / sizeof(arr[0]); - - cout << "Char | Huffman code "; - cout << "\n----------------------\n"; + printf(" Char | Huffman code "); + printf("\n--------------------\n"); HuffmanCodes(arr, freq, size); } ``` -### C -```c -// Huffman Coding in C +### CPP +```cpp +// Huffman Coding in C++ -#include -#include +#include +using namespace std; #define MAX_TREE_HT 50 struct MinHNode { - char item; unsigned freq; + char item; struct MinHNode *left, *right; }; -struct MinHeap { +struct MinH { unsigned size; unsigned capacity; struct MinHNode **array; }; -// Create nodes +// Creating Huffman tree node struct MinHNode *newNode(char item, unsigned freq) { struct MinHNode *temp = (struct MinHNode *)malloc(sizeof(struct MinHNode)); @@ -266,19 +226,25 @@ struct MinHNode *newNode(char item, unsigned freq) { return temp; } -// Create min heap -struct MinHeap *createMinH(unsigned capacity) { - struct MinHeap *minHeap = (struct MinHeap *)malloc(sizeof(struct MinHeap)); - +// Create min heap using given capacity +struct MinH *createMinH(unsigned capacity) { + struct MinH *minHeap = (struct MinH *)malloc(sizeof(struct MinH)); minHeap->size = 0; - minHeap->capacity = capacity; - minHeap->array = (struct MinHNode **)malloc(minHeap->capacity * sizeof(struct MinHNode *)); return minHeap; } -// Function to swap +// Print the array +void printArray(int arr[], int n) { + int i; + for (i = 0; i < n; ++i) + cout << arr[i]; + + cout << "\n"; +} + +// Swap function void swapMinHNode(struct MinHNode **a, struct MinHNode **b) { struct MinHNode *t = *a; *a = *b; @@ -286,7 +252,7 @@ void swapMinHNode(struct MinHNode **a, struct MinHNode **b) { } // Heapify -void minHeapify(struct MinHeap *minHeap, int idx) { +void minHeapify(struct MinH *minHeap, int idx) { int smallest = idx; int left = 2 * idx + 1; int right = 2 * idx + 2; @@ -298,18 +264,19 @@ void minHeapify(struct MinHeap *minHeap, int idx) { smallest = right; if (smallest != idx) { - swapMinHNode(&minHeap->array[smallest], &minHeap->array[idx]); + swapMinHNode(&minHeap->array[smallest], + &minHeap->array[idx]); minHeapify(minHeap, smallest); } } // Check if size if 1 -int checkSizeOne(struct MinHeap *minHeap) { +int checkSizeOne(struct MinH *minHeap) { return (minHeap->size == 1); } -// Extract min -struct MinHNode *extractMin(struct MinHeap *minHeap) { +// Extract the min +struct MinHNode *extractMin(struct MinH *minHeap) { struct MinHNode *temp = minHeap->array[0]; minHeap->array[0] = minHeap->array[minHeap->size - 1]; @@ -319,8 +286,8 @@ struct MinHNode *extractMin(struct MinHeap *minHeap) { return temp; } -// Insertion function -void insertMinHeap(struct MinHeap *minHeap, struct MinHNode *minHeapNode) { +// Insertion +void insertMinHeap(struct MinH *minHeap, struct MinHNode *minHeapNode) { ++minHeap->size; int i = minHeap->size - 1; @@ -328,10 +295,12 @@ void insertMinHeap(struct MinHeap *minHeap, struct MinHNode *minHeapNode) { minHeap->array[i] = minHeap->array[(i - 1) / 2]; i = (i - 1) / 2; } + minHeap->array[i] = minHeapNode; } -void buildMinHeap(struct MinHeap *minHeap) { +// BUild min heap +void buildMinHeap(struct MinH *minHeap) { int n = minHeap->size - 1; int i; @@ -343,8 +312,8 @@ int isLeaf(struct MinHNode *root) { return !(root->left) && !(root->right); } -struct MinHeap *createAndBuildMinHeap(char item[], int freq[], int size) { - struct MinHeap *minHeap = createMinH(size); +struct MinH *createAndBuildMinHeap(char item[], int freq[], int size) { + struct MinH *minHeap = createMinH(size); for (int i = 0; i < size; ++i) minHeap->array[i] = newNode(item[i], freq[i]); @@ -355,9 +324,9 @@ struct MinHeap *createAndBuildMinHeap(char item[], int freq[], int size) { return minHeap; } -struct MinHNode *buildHuffmanTree(char item[], int freq[], int size) { +struct MinHNode *buildHfTree(char item[], int freq[], int size) { struct MinHNode *left, *right, *top; - struct MinHeap *minHeap = createAndBuildMinHeap(item, freq, size); + struct MinH *minHeap = createAndBuildMinHeap(item, freq, size); while (!checkSizeOne(minHeap)) { left = extractMin(minHeap); @@ -372,49 +341,39 @@ struct MinHNode *buildHuffmanTree(char item[], int freq[], int size) { } return extractMin(minHeap); } - void printHCodes(struct MinHNode *root, int arr[], int top) { if (root->left) { arr[top] = 0; printHCodes(root->left, arr, top + 1); } + if (root->right) { arr[top] = 1; printHCodes(root->right, arr, top + 1); } if (isLeaf(root)) { - printf(" %c | ", root->item); + cout << root->item << " | "; printArray(arr, top); } } // Wrapper function void HuffmanCodes(char item[], int freq[], int size) { - struct MinHNode *root = buildHuffmanTree(item, freq, size); + struct MinHNode *root = buildHfTree(item, freq, size); int arr[MAX_TREE_HT], top = 0; printHCodes(root, arr, top); } -// Print the array -void printArray(int arr[], int n) { - int i; - for (i = 0; i < n; ++i) - printf("%d", arr[i]); - - printf("\n"); -} - int main() { char arr[] = {'A', 'B', 'C', 'D'}; int freq[] = {5, 1, 6, 3}; int size = sizeof(arr) / sizeof(arr[0]); - printf(" Char | Huffman code "); - printf("\n--------------------\n"); - + cout << "Char | Huffman code "; + cout << "\n----------------------\n"; HuffmanCodes(arr, freq, size); } ```