Description: Given arrays recording 'Preorder and Inorder' Traversal (Problem 105) or  'Inorder and Postorder' (Problem 106), u need build the binary tree. Input: 105. Preorder & Inorder traversal 106. Inorder & Postorder traversal output: A binar…

题目: Given inorder and postorder traversal of a tree, construct the binary tree. Note:You may assume that duplicates do not exist in the tree. 提示: 题目要求通过一颗二叉树的中序遍历及后续遍历的结果,将这颗二叉树构建出来,另外还有一个已知条件,所有节点的值都是不同的. 首先需要了解一下二叉树不同遍历方式的定义: 前序遍历:首先访问根结点,然后遍历左子树,最…

Given preorder and inorder traversal of a tree, construct the binary tree. Note: You may assume that duplicates do not exist in the tree. For example, given preorder = [3,9,20,15,7] inorder = [9,3,15,20,7] Return the following binary tree: 3 / \ 9 20…

题目 Given preorder and inorder traversal of a tree, construct the binary tree. Note: You may assume that duplicates do not exist in the tree. 分析 给定一颗二叉树的前序和中序遍历序列,求该二叉树. 我们手动做过很多这样的题目,掌握了其规则~ 前序遍历第一个元素为树的root节点,然后在中序序列中查找该值,元素左侧为左子树,右侧为右子树: 求出左子树个数cou…

[LeetCode]Minimum Depth of Binary Tree 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. 递归和非递归,此提比较简单.广度优先遍历即可.关键之处就在于如何保持访问深度. 下面是4种代码: im…

这道题是LeetCode里的第104道题. 给出题目: 给定一个二叉树,找出其最大深度. 二叉树的深度为根节点到最远叶子节点的最长路径上的节点数. 说明: 叶子节点是指没有子节点的节点. 示例: 给定二叉树 [3,9,20,null,null,15,7], 3 / \ 9 20 / \ 15 7 返回它的最大深度 3 . DFS 递归算法,简单的二叉树题.如果看不懂代码,建议学习一下二叉树,这可是基础啊! 给出代码: 递归法: /** * Definition for a binary tree…

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 DFS BFS 日期 题目地址:https://leetcode.com/problems/cousins-in-binary-tree/ 题目描述 In a binary tree, the root node is at depth 0, and children of each depth k node are at depth k+1. Tw…

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 递归 日期 题目地址:https://leetcode.com/problems/diameter-of-binary-tree/#/description 题目描述 Given a binary tree, you need to compute the length of the diameter of the tree. The diameter…

题目简述: 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. 解题思路: # Definition for a binary tree node # class TreeNode: # def __init__(self, x):…

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. 简单题,不过注意叶子结点是两个子树都是NULL的指针.只有一个子树NULL的不是. struct TreeNode { int val; TreeNode *left; TreeN…

题目如下: 解题思路:最长的周长一定是树中某一个节点(不一定是根节点)的左右子树中的两个叶子节点之间的距离,所以最简单的办法就是把树中所有节点的左右子树中最大的两个叶子节点之间的距离求出来,最终得到最大值. 代码如下: # Definition for a binary tree node. class TreeNode(object): def __init__(self, x): self.val = x self.left = None self.right = None class So…

题目如下: In a binary tree, the root node is at depth 0, and children of each depth k node are at depth k+1. Two nodes of a binary tree are cousins if they have the same depth, but have different parents. We are given the root of a binary tree with uniqu…

http://oj.leetcode.com/problems/maximum-depth-of-binary-tree/ public class Solution { public int maxDepth(TreeNode root) { if(root!=null){ int depth=0; InOrder(root,depth); } return max; } public int max=0; private void InOrder(TreeNode root, int dep…

一天一道LeetCode 本系列文章已全部上传至我的github,地址:ZeeCoder's Github 欢迎大家关注我的新浪微博,我的新浪微博 欢迎转载,转载请注明出处 (一)题目 来源:https://leetcode.com/problems/construct-binary-tree-from-inorder-and-postorder-traversal/ Given inorder and postorder traversal of a tree, construct the b…

[LeetCode]106. Construct Binary Tree from Inorder and Postorder Traversal 解题报告(Python) 标签: LeetCode 题目地址:https://leetcode.com/problems/construct-binary-tree-from-inorder-and-postorder-traversal/description/ 题目描述: Given inorder and postorder traversal…

Construct Binary Tree from Preorder and Inorder Traversal Given preorder and inorder traversal of a tree, construct the binary tree. Note:You may assume that duplicates do not exist in the tree. 可与Construct Binary Tree from Inorder and Postorder Trav…

Given preorder and inorder traversal of a tree, construct the binary tree. Note:You may assume that duplicates do not exist in the tree. For example, given preorder = [3,9,20,15,7] inorder = [9,3,15,20,7] Return the following binary tree: 3 / \ 9 20…

Given inorder and postorder traversal of a tree, construct the binary tree. Note:You may assume that duplicates do not exist in the tree. For example, given inorder = [9,3,15,20,7] postorder = [9,15,7,20,3] Return the following binary tree: 3 / \ 9 2…

Given inorder and postorder traversal of a tree, construct the binary tree. Note:You may assume that duplicates do not exist in the tree. For example, given inorder = [9,3,15,20,7] postorder = [9,15,7,20,3] Return the following binary tree: 3 / \ 9 2…

Given preorder and inorder traversal of a tree, construct the binary tree. Note:You may assume that duplicates do not exist in the tree. For example, given preorder = [3,9,20,15,7] inorder = [9,3,15,20,7] Return the following binary tree: 3 / \ 9 20…

Given inorder and postorder traversal of a tree, construct the binary tree. Note:You may assume that duplicates do not exist in the tree. For example, given inorder = [9,3,15,20,7] postorder = [9,15,7,20,3] Return the following binary tree: 3 / \ 9 2…

LeetCode 原题链接 Construct Binary Tree from Inorder and Postorder Traversal - LeetCode Construct Binary Tree from Preorder and Postorder Traversal - LeetCode 题目大意 给定一棵二叉树的中序遍历和后序遍历,求这棵二叉树的结构. 给定一棵二叉树的前序遍历和中序遍历,求这棵二叉树的结构. 样例 Input: inorder = [9, 3, 15, 2…

LeetCode:Construct Binary Tree from Inorder and Postorder Traversal Given inorder and postorder traversal of a tree, construct the binary tree. Note:You may assume that duplicates do not exist in the tree.                                            …

Given preorder and inorder traversal of a tree, construct the binary tree. Note:You may assume that duplicates do not exist in the tree. 这道题要求用先序和中序遍历来建立二叉树,跟之前那道Construct Binary Tree from Inorder and Postorder Traversal 由中序和后序遍历建立二叉树原理基本相同,针对这道题,由于先…

[CF438E]The Child and Binary Tree(多项式运算,生成函数) 题面 有一个大小为\(n\)的集合\(S\) 问所有点权都在集合中,并且点权之和分别为\([0,m]\)的二叉树的个数. \(n,m<=10^5\) 题解 设\(f(i)\)表示点权和为\(i\)的二叉树个数,\(c(i)\)是集合中数的生成函数,那么我们可以得到 \[f(n)=\sum_{i=1}^{n}c(i)\sum_{j=0}^{n-i}f(j)f(n-i-j)\] 显然有\(f(0)=1\) 构…

原题链接在这里:https://leetcode.com/problems/construct-binary-tree-from-preorder-and-postorder-traversal/ 题目: Return any binary tree that matches the given preorder and postorder traversals. Values in the traversals pre and post are distinct positive intege…

Return any binary tree that matches the given preorder and postorder traversals. Values in the traversals pre and post are distinct positive integers. Example 1: Input: pre = [1,2,4,5,3,6,7], post = [4,5,2,6,7,3,1] Output: [1,2,3,4,5,6,7] Note: 1 <=…

Construct Binary Tree from Preorder and Inorder Traversal Given preorder and inorder traversal of a tree, construct the binary tree. Note:You may assume that duplicates do not exist in the tree. SOLUTION 1: 1. Find the root node from the preorder.(it…

Construct Binary Tree from Inorder and Postorder Traversal OJ: https://oj.leetcode.com/problems/construct-binary-tree-from-inorder-and-postorder-traversal/ Given inorder and postorder traversal of a tree, construct the binary tree. Note: You may assu…

Construct Binary Tree from Preorder and Inorder Traversal Given preorder and inorder traversal of a tree, construct the binary tree. 分析: 根据前序遍历和中序遍历构造一棵树,递归求解即可 /** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left;…