LeetCode1161. Maximum Level Sum of a Binary Tree

文章目录

一、题目

Given the root of a binary tree, the level of its root is 1, the level of its children is 2, and so on.

Return the smallest level x such that the sum of all the values of nodes at level x is maximal.

Example 1:

Input: root = [1,7,0,7,-8,null,null]

Output: 2

Explanation:

Level 1 sum = 1.

Level 2 sum = 7 + 0 = 7.

Level 3 sum = 7 + -8 = -1.

So we return the level with the maximum sum which is level 2.

Example 2:

Input: root = [989,null,10250,98693,-89388,null,null,null,-32127]

Output: 2

Constraints:

The number of nodes in the tree is in the range [1, 104].

-105 <= Node.val <= 105

二、题解

cpp 复制代码
/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    int maxLevelSum(TreeNode* root) {
        int res = 1;
        int maxSum = INT_MIN;
        queue<TreeNode*> q;
        q.push(root);
        int level = 0;
        while(!q.empty()){
            int size = q.size();
            int sum = 0;
            level++;
            while(size--){
                TreeNode* t = q.front();
                q.pop();
                sum += t->val;
                if(t->left) q.push(t->left);
                if(t->right) q.push(t->right);
            }
            if(sum > maxSum){
                maxSum = sum;
                res = level;
            }
        }
        return res;
    }
};
相关推荐
今天背单词了吗98013 分钟前
算法学习笔记:7.Dijkstra 算法——从原理到实战,涵盖 LeetCode 与考研 408 例题
java·开发语言·数据结构·笔记·算法
气质、小青年!21 分钟前
【排序算法】
c语言·数据结构
重庆小透明1 小时前
力扣刷题记录【1】146.LRU缓存
java·后端·学习·算法·leetcode·缓存
desssq2 小时前
力扣:70. 爬楼梯
算法·leetcode·职场和发展
clock的时钟2 小时前
暑期数据结构第一天
数据结构·算法
小小小小王王王3 小时前
求猪肉价格最大值
数据结构·c++·算法
岁忧3 小时前
(LeetCode 面试经典 150 题 ) 58. 最后一个单词的长度 (字符串)
java·c++·算法·leetcode·面试·go
BIYing_Aurora3 小时前
【IPMV】图像处理与机器视觉:Lec13 Robust Estimation with RANSAC
图像处理·人工智能·算法·计算机视觉
码农编程录4 小时前
【c/c++3】类和对象,vector容器,类继承和多态,systemd,std&boost
c++
martian6655 小时前
支持向量机(SVM)深度解析:从数学根基到工程实践
算法·机器学习·支持向量机