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LeetCode-117-Populating-Next-Right-Pointers-in-Each-Node-II.java
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LeetCode-117-Populating-Next-Right-Pointers-in-Each-Node-II.java
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/*
// Definition for a Node.
class Node {
public int val;
public Node left;
public Node right;
public Node next;
public Node() {}
public Node(int _val,Node _left,Node _right,Node _next) {
val = _val;
left = _left;
right = _right;
next = _next;
}
};
*/
class Solution {
// BFS
// Do level order traversal, the same solution as (https://leetcode.com/problems/populating-next-right-pointers-in-each-node/)
// public Node connect(Node root) {
// if (root == null) return root;
// Queue<Node> queue = new LinkedList<>();
// queue.offer(root);
// while (!queue.isEmpty()) {
// int size = queue.size();
// Node prev = null;
// for (int i = 0; i < size; i++) {
// Node curr = queue.poll();
// if (prev != null) {
// prev.next = curr;
// }
// prev = curr;
// if (curr.left != null) queue.offer(curr.left);
// if (curr.right != null) queue.offer(curr.right);
// }
// }
// return root;
// }
// Level order traversal
public Node connect(Node root) {
if (root == null) return root;
Node levelCurr = root;
while (levelCurr != null) {
Node dummy = new Node(-1);
Node prev = dummy;
while (levelCurr != null) {
if (levelCurr.left != null) {
prev.next = levelCurr.left;
prev = prev.next;
}
if (levelCurr.right != null) {
prev.next = levelCurr.right;
prev = prev.next;
}
levelCurr = levelCurr.next;
}
levelCurr = dummy.next;
}
return root;
}
}