05 August 2008
返回二叉树层序值和最大的的那一层，从1开始
层序遍历
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/**
* 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 maxLevelSum(TreeNode root) {
if (root == null) return 0;
Queue<TreeNode> queue = new LinkedList<>();
queue.add(root);
int level = 0;
int minLevel = 0, maxSum = Integer.MIN_VALUE;
while (!queue.isEmpty()) {
int size = queue.size();
level++;
int levelSum = 0;
for (int i = 0; i < size; i++) {
TreeNode node = queue.poll();
levelSum += node.val;
if (node.left != null) queue.add(node.left);
if (node.right != null) queue.add(node.right);
}
if (levelSum > maxSum) {
maxSum = levelSum;
minLevel = level;
}
}
return minLevel;
}
}