Maximum Level Sum of a Binary Tree
给一个二叉树, 求最大的sum的一层node. 层序扫描
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
class Solution {
public int maxLevelSum(TreeNode root) {
Queue<TreeNode> q = new LinkedList<>();
q.add(root);
int max = Integer.MIN_VALUE;
int maxIndex = -1;
int lvl = 1;
while(!q.isEmpty()) {
int size = q.size();
int local = 0;
for(int i = 0; i < size; i++) {
TreeNode node = q.poll();
if(node.left != null)
q.add(node.left);
if(node.right != null)
q.add(node.right);
local += node.val;
}
if(local > max){
max = local;
maxIndex = lvl;
}
lvl++;
}
return maxIndex;
}
}