/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode() {}
* TreeNode(int val) { this.val = val; }
* TreeNode(int val, TreeNode left, TreeNode right) {
* this.val = val;
* this.left = left;
* this.right = right;
* }
* }
*/
class Solution {
public int widthOfBinaryTree(TreeNode root) {
if (root == null)
return 0;
int ans = 0;
Deque<Pair<TreeNode, Integer>> q = new ArrayDeque<>(); // {node, index}
q.offer(new Pair<>(root, 1));
while (!q.isEmpty()) {
final int offset = q.peekFirst().getValue() * 2;
ans = Math.max(ans, q.peekLast().getValue() - q.peekFirst().getValue() + 1);
for (int sz = q.size(); sz > 0; --sz) {
final TreeNode node = q.peekFirst().getKey();
final int index = q.pollFirst().getValue();
if (node.left != null)
q.offer(new Pair<>(node.left, index * 2 - offset));
if (node.right != null)
q.offer(new Pair<>(node.right, index * 2 + 1 - offset));
}
}
return ans;
}
}
leetcode
challenge
Here is the link for the problem:
https://leetcode.com/problems/maximum-width-of-binary-tree/
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