Vasya has a tree consisting of n n vertices with root in vertex 1 1 . At first all vertices has 0 0 written on it. Let d(i,j) d(i,j) be the distance between vertices i i and j j , i.e. number of edges in the shortest path from i i to j j . Also, let'…
题目链接:传送门 题目: E. Vasya and a Tree time limit per test seconds memory limit per test megabytes input standard input output standard output Vasya has a tree consisting of n vertices with root . At first all vertices has written on it. Let d(i,j) be the…
CodeForces - 1076E Problem Description: Vasya has a tree consisting of n vertices with root in vertex 1. At first all vertices has 0 written on it. Let d(i,j) be the distance between vertices i and j, i.e. number of edges in the shortest path from i…
leetcode算法: Find Bottom Left Tree ValueGiven a binary tree, find the leftmost value in the last row of the tree.Example 1:Input: 2 / \ 1 3Output:1Example 2: Input: 1 / \ 2 3 / / \ 4 5 6 / 7Output:7Note: You may assume the tree (i.e., the given root n…
E - Vasya and a Tree 思路: dfs动态维护关于深度树状数组 返回时将当前节点的所有操作删除就能保证每次访问这个节点时只进行过根节点到当前节点这条路径上的操作 代码: #pragma GCC optimize(2) #pragma GCC optimize(3) #pragma GCC optimize(4) #include<bits/stdc++.h> using namespace std; #define fi first #define se second #de…
题目:验证二叉搜索树 难度:Medium 题目内容: Given a binary tree, determine if it is a valid binary search tree (BST). Assume a BST is defined as follows: The left subtree of a node contains only nodes with keys less than the node's key. The right subtree of a node co…
二叉搜索树是常用的概念,它的定义如下: The left subtree of a node contains only nodes with keys less than the node's key. The right subtree of a node contains only nodes with keys greater than the node's key. Both the left and right subtrees must also be binary search…
题面 Vasya has a tree consisting of n vertices with root in vertex 1. At first all vertices has 0 written on it. Let d(i,j) be the distance between vertices i and j, i.e. number of edges in the shortest path from i to j. Also, let's denote k-subtree of…
题目来源 https://leetcode.com/problems/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 d…
题目描述: A tree is a well-known data structure that is either empty (null, void, nothing) or is a set of one or more nodes connected by directed edges between nodes satisfying the following properties. There is exactly one node, called the root, to whic…
题目来源: https://leetcode.com/problems/recover-binary-search-tree/ 题意分析: 二叉搜索树中有两个点错了位置,恢复这棵树. 题目思路: 如果是没有空间复杂度限制还是比较简单.首先将树的值取出来,然后排序,将相应的位置判断是否正确.如果要特定空间复杂度就难很多. 代码(python): # Definition for a binary tree node. # class TreeNode(object): # def __init__…
题目链接 题目要求: Given a binary tree, determine if it is a valid binary search tree (BST). Assume a BST is defined as follows: The left subtree of a node contains only nodes with keys less than the node's key. The right subtree of a node contains only node…
题目说明 Given a binary tree, flatten it to a linked list in-place. For example, Given 1 / \ 2 5 / \ \ 3 4 6 The flattened tree should look like: 1 \ 2 \ 3 \ 4 \ 5 \ 6 题目分析 第一感觉是前序遍历,顺便打算在这题练习一下昨天学到的二级指针的写法XD,调的时候bug挺多的,可读性贼差,指针还是慎用啊-- 以下为个人实现(C++,12ms):…
既上篇关于二叉搜索树的文章后,这篇文章介绍一种针对二叉树的新的中序遍历方式,它的特点是不需要递归或者使用栈,而是纯粹使用循环的方式,完成中序遍历. 线索二叉树介绍 首先我们引入“线索二叉树”的概念: "A binary tree is threaded by making all right child pointers that would normally be null point to the inorder successor of the node, and all left chi…
Two elements of a binary search tree (BST) are swapped by mistake. Recover the tree without changing its structure. 首先是O(N)空间的方法,用递归: /** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeN…
Is It A Tree? 题目链接:http://poj.org/problem?id=1308 Description: A tree is a well-known data structure that is either empty (null, void, nothing) or is a set of one or more nodes connected by directed edges between nodes satisfying the following proper…
Given a binary tree, determine if it is a valid binary search tree (BST). Assume a BST is defined as follows: The left subtree of a node contains only nodes with keys less than the node's key. The right subtree of a node contains only nodes with keys…
