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

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…

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…

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…

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…

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…

［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,…

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…

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…

▶ 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…

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…

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…

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…

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,…

题目如下: Given a binary tree, determine if it is a complete binary tree. Definition of a complete binary tree from Wikipedia:In a complete binary tree every level, except possibly the last, is completely filled, and all nodes in the last level are as fa…

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 BFS DFS 日期 题目地址:https://leetcode.com/problems/check-completeness-of-a-binary-tree/ 题目描述 Given a binary tree, determine if it is a complete binary tree. Definition of a complete…

1. Description One way to serialize a binary tree is to use pre-order traversal. When we encounter a non-null node, we record the node's value. If it is a null node, we record using a sentinel value such as #. _9_ / \ 3 2 / \ / \ 4 1 # 6 / \ / \ / \…

题目: 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 a…

题目如下: In an infinite binary tree where every node has two children, the nodes are labelled in row order. In the odd numbered rows (ie., the first, third, fifth,...), the labelling is left to right, while in the even numbered rows (second, fourth, six…

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…

[AGC009E]Eternal Average 题面 洛谷 题解 神仙题.jpg 我们把操作看成一棵\(k\)叉树,其中每个节点有权值,所有叶子节点(共\(n+m\)个)就是\(0\)或\(1\). 出了叶子节点外的所有节点就代表一次合并,权值就是他们的平均值. 设一开始\(0\)点的深度分别为\(x_1,x_2...x_n\),\(1\)的深度为\(y_1,y_2...y_m\). 那么根节点的权值为\(\sum (\frac 1k) ^ {y_i}\),而如果我们将所有点的权值改为\(1\…

[BZOJ2555]SubString(后缀自动机,Link-Cut Tree) 题面 BZOJ 题解 这题看起来不难 每次要求的就是\(right/endpos\)集合的大小 所以搞一个\(LCT\)维护一下\(SAM\)的\(Parent\)树就好了 但是代码一点都不好写(我还是对着黄学长的调的...) 于是乎我也学着魔改了一下\(LCT\) #include<iostream> #include<cstdio> #include<cstdlib> #include…

[UOJ207]共价大爷游长沙(Link-Cut Tree,随机化) 题面 UOJ 题解 这题太神了 \(\%\%\%myy\) 看到动态的维护边很容易的想到了\(LCT\) 然后能否堵住一条路 我们也不难想到,以这条路的一个端点为根的子数 是否恰好包含了集合中所有点对的中的恰好一个点 但是怎么算恰好包括了一个点... 不会呀... \(\%\%\%myy\)神奇的随机算法 对于每个点对, 就给这两个点随便随机一个点权 维护子树异或和 这样就可以检查子树异或和是否恰好和所有权值的异或和相等 把随…

[LeetCode]109. Convert Sorted List to Binary Search Tree 解题报告(Python) 标签(空格分隔): LeetCode 作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.me/ 题目地址:https://leetcode.com/problems/convert-sorted-list-to-binary-search-tree/description/ 题目描述: Given a s…