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;
    }
}

/**

* 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;

}

Maximum Level Sum of a Binary Tree

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