Question 637. Average of Levels in Binary Tree Solution 思路:定义一个map,层数作为key,value保存每层的元素个数和所有元素的和,遍历这个树,把map里面填值,遍历结束后,再遍历这个map,把每层的平均数放到数组里,最后数组转为list返回,不用考虑list里的排序了. Java实现: /** * Definition for a binary tree node. * public class TreeNode { * int v…

problem 637. Average of Levels in Binary Tree 参考 1. Leetcode_easy_637. Average of Levels in Binary Tree; 完…

Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array. Example 1: Input: 3 / \ 9 20 / \ 15 7 Output: [3, 14.5, 11] Explanation: The average value of nodes on level 0 is 3, on level 1 is 14.5, and o…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 方法一:DFS 方法二:BFS 日期 题目地址:https://leetcode.com/submissions/detail/136579829/ 题目描述 Given a non-empty binary tree, return the average value of the nodes on each level in the form o…

题目要求 Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array. 题目分析及思路 给定一棵非空二叉树,要求以列表的形式返回每一层结点值的平均值.可以使用队列保存结点,进行层次遍历,要特别注意空结点的判断. python代码 # Definition for a binary tree node. # class TreeNode: # …

题目: Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array. Example 1: Input: 3 / \ 9 20 / \ 15 7 Output: [3, 14.5, 11] Explanation: The average value of nodes on level 0 is 3, on level 1 is 14.5, a…

Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array. Example 1: Input: 3 / \ 9 20 / \ 15 7 Output: [3, 14.5, 11] Explanation: The average value of nodes on level 0 is 3, on level 1 is 14.5, and o…

Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array. Example 1: Input: 3 / \ 9 20 / \ 15 7 Output: [3, 14.5, 11] Explanation: The average value of nodes on level 0 is 3, on level 1 is 14.5, and o…

Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array. Example 1: <b>Input:</b> 3 / \ 9 20 / \ 15 7 Output: [3, 14.5, 11] Explanation: The average value of nodes on level 0 is 3, on level 1…

原题 Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array. Example 1: Input: 3 / 9 20 / 15 7 Output: [3, 14.5, 11] Explanation: The average value of nodes on level 0 is 3, on level 1 is 14.5, and on…

Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array. Example 1: Input: 3 / \ 9 20 / \ 15 7 Output: [3, 14.5, 11] Explanation: The average value of nodes on level 0 is 3, on level 1 is 14.5, and o…

［抄题］: Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array. Example 1: Input: 3 / \ 9 20 / \ 15 7 Output: [3, 14.5, 11] Explanation: The average value of nodes on level 0 is 3, on level 1 is 14.5,…

▶ 有关将一棵二叉树转化为二位表的题目,一模一样的套路出了四道题 ▶ 第 102 题,简单的转化,[ 3, 9, 20, null, null, 15, 7 ] 转为 [ [ 15, 7 ] , [ 9, 20 ] , [ 3 ] ] ● 自己的代码,6 ms,先根序遍历,最快的解法算法与之相同 class Solution { public: void visit(TreeNode* root, vector<vector<int>>& table, int level)…

637. 二叉树的层平均值 637. Average of Levels in Binary Tree LeetCode637. Average of Levels in Binary Tree 题目描述 给定一个非空二叉树, 返回一个由每层节点平均值组成的数组. 示例 1: 输入: 3 / \ 9 20 / \ 15 7 输出: [3, 14.5, 11] 解释: 第 0 层的平均值是 3,第 1 层是 14.5,第 2 层是 11.因此返回 [3, 14.5, 11]. 注意: 节点值的范围…

Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array.Example 1:Input: 3 / \ 9 20 / \ 15 7Output: [3, 14.5, 11]Explanation:The average value of nodes on level 0 is 3, on level 1 is 14.5, and on lev…

Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array. Example 1: Input: 3 / \ 9 20 / \ 15 7 Output: [3, 14.5, 11] Explanation: The average value of nodes on level 0 is 3, on level 1 is 14.5, and o…

这是悦乐书的第277次更新,第293篇原创 01 看题和准备 今天介绍的是LeetCode算法题中Easy级别的第145题(顺位题号是637).给定一个非空二叉树,以数组的形式返回每一层节点值之和的平均值.例如: 3 / \ 9 20 / \ 15 7 输出:[3,14.5,11] 说明:第一层上的节点的平均值为3,第二层上的节点的平均值为14.5,第三层上的节点的平均值为11.因此返回[3,14.5,11]. 注意:节点值的范围在32位有符号整数的范围内. 本次解题使用的开发工具是eclips…

问题描述: Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array. Example 1: Input: 3 / \ 9 20 / \ 15 7 Output: [3, 14.5, 11] Explanation: The average value of nodes on level 0 is 3, on level 1 is 14.5,…

Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array. Example 1: Input: 3 / \ 9 20 / \ 15 7 Output: [3, 14.5, 11] Explanation: The average value of nodes on level 0 is 3, on level 1 is 14.5, and o…

Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array. Example 1: Input: 3 / \ 9 20 / \ 15 7 Output: [3, 14.5, 11] Explanation: The average value of nodes on level 0 is 3, on level 1 is 14.5, and o…

给定一个非空二叉树, 返回一个由每层节点平均值组成的数组. class Solution { public: vector<double> averageOfLevels(TreeNode* root) { vector<double> res; if(root == NULL) return res; queue<TreeNode*> q; q.push(root); while(!q.empty()) { int len = q.size(); double sum…

Given a binary tree, find its minimum depth. The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node. https://leetcode.com/problems/minimum-depth-of-binary-tree/ 题意就是给定一个二叉树,找出从根节点到叶子节点最低的高度,直…

Given a binary tree, determine if it is height-balanced. For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1. Solution:  bool helperBalanced(int…

Given a binary tree, find its minimum depth. The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node. Summary: BFS or DFS with recursion. int minDepth(TreeNode *root) { if(root == NULL) ; if(r…

110.Balanced Binary Tree Given a binary tree, determine if it is height-balanced. For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1. 很早以前做的了  准…

Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes v and w as the lowest node in T that has both v and w…

Invert a binary tree. 4 / \ 2 7 / \ / \ 1 3 6 9 to 4 / \ 7 2 / \ / \ 9 6 3 1 Trivia:This problem was inspired by this original tweet by Max Howell: Google: 90% of our engineers use the software you wrote (Homebrew), but you can’t invert a binary tree…

Given a binary tree, determine if it is height-balanced. For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1. 题意:给定一个二叉树,判断是否是高度平衡的,这里的高度平衡定义是每个节…

Given a binary tree, find its maximum depth. The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node. Subscribe to see which companies asked this question 非递归实现: int maxDepth(TreeNode* root) {…

Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes v and w as the lowest node in T that has both v and w…