1094 - Farthest Nodes in a Tree PDF (English) Statistics Forum Time Limit: 2 second(s) Memory Limit: 32 MB Given a tree (a connected graph with no cycles), you have to find the farthest nodes in the tree. The edges of the tree are weighted and undire…

http://lightoj.com/volume_showproblem.php?problem=1094 树的直径是指树的最长简单路. 求法: 两遍BFS :先任选一个起点BFS找到最长路的终点,再从终点进行BFS,则第二次BFS找到的最长路即为树的直径: 原理: 设起点为u,第一次BFS找到的终点v一定是树的直径的一个端点 证明: 1) 如果u 是直径上的点,则v显然是直径的终点(因为如果v不是的话,则必定存在另一个点w使得u到w的距离更长,则于BFS找到了v矛盾)2) 如果u不是直径上的…

http://acm.hust.edu.cn/vjudge/contest/121398#problem/H 不是特别理解,今天第一次碰到这种问题.给个链接看大神的解释吧 http://www.cnblogs.com/qq2424260747/p/4740347.html #include <cstdio> #include <cstring> #include <iostream> #include <cmath> #include<vector&g…

1094 - Farthest Nodes in a Tree problem=1094" style="color:rgb(79,107,114)"> problem=1094&language=english&type=pdf" style="color:rgb(79,107,114)">PDF (English) Statistics Forum Time Limit: 2 second(s) Memory Li…

1094 - Farthest Nodes in a Tree   PDF (English) Statistics Forum Time Limit: 2 second(s) Memory Limit: 32 MB Given a tree (a connected graph with no cycles), you have to find the farthest nodes in the tree. The edges of the tree are weighted and undi…

题目链接:http://lightoj.com/volume_showproblem.php?problem=1094 Given a tree (a connected graph with no cycles), you have to find the farthest nodes in the tree. The edges of the tree are weighted and undirected. That means you have to find two nodes in…

http://lightoj.com/volume_showproblem.php?problem=1094 Given a tree (a connected graph with no cycles), you have to find the farthest nodes in the tree. The edges of the tree are weighted and undirected. That means you have to find two nodes in the t…

题目链接,密码:hpu Description Given a tree (a connected graph with no cycles), you have to find the farthest nodes in the tree. The edges of the tree are weighted and undirected. That means you have to find two nodes in the tree whose distance is maximum a…

Given a tree (a connected graph with no cycles), you have to find the farthest nodes in the tree. The edges of the tree are weighted and undirected. That means you have to find two nodes in the tree whose distance is maximum amongst all nodes. Input…

树上最远点对(树的直径) 做法1:树形dp 最长路一定是经过树上的某一个节点的. 因此: an1[i],an2[i]分别表示一个点向下的最长链和次长链,次长链不存在就设为0:这两者很容易求 an3[i]表示i为根的子树中的答案:an3[u]=max(max{an3[v]}(v是u的子节点),an1[u]+an2[u]) #include<cstdio> #include<cstring> #include<queue> #include<algorithm>…

题目链接:http://www.lightoj.com/volume_showproblem.php?problem=1257 跟hdu2196一样,两次dfs //#pragma comment(linker, "/STACK:102400000, 102400000") #include <algorithm> #include <iostream> #include <cstdlib> #include <cstring> #inc…

题目给一棵树,边带有权值,求每一点到其他点路径上的最大权和. 树上任意两点的路径都可以看成是经过某棵子树根的路径,即路径权=两个点到根路径权的和,于是果断树分治. 对于每次分治的子树,计算其所有结点到根的距离:对于每个结点,找到另一个离根最远的且与该结点路径过根的结点,二者的距离和就是这个点在过这棵子树的根能到的最远距离. 现在问题就是怎么比较快地找到这另一个最远距离的点..两点路径过根,说明两点间不存在一点是另一点的祖先..我一开始还想用DFS序+线段树来着..想了想,想出了线性的算法: 记录…

Farthest Nodes in a Tree Time Limit: 2000MS Memory Limit: 32768KB 64bit IO Format: %lld & %llu Submit Status Description Given a tree (a connected graph with no cycles), you have to find the farthest nodes in the tree. The edges of the tree are weigh…

Given a very large n-ary tree. Where the root node has some information which it wants to pass to all of its children down to the leaves with the constraint that it can only pass the information to one of its children at a time (take it as one iterat…

给一个 二叉树 , 求最深节点的最小公共父节点 . retrun . 先用 recursive , 很快写出来了, 要求用 iterative . 时间不够了... Recursion: 返回的时候返回lca和depth,每个node如果有大于一个子节点的depth相同就返回这个node,如果有一个子节点depth更深就返回个子节点lca,这个o(n)就可以了 Iteration: tree的recursion换成iteration处理,一般用stack都能解决吧(相当于手动用stack模拟re…

June 8, 2015 我最喜欢的一道算法题目, 二行代码. 编程序需要很强的逻辑思维, 严密,我还没有很好训练自己．想一想, 二行代码, 五分钟就可以搞定; 最近这几天网上大家热议的 Homebrew 的作者 Max Howell 面试 Google 挂掉的一题, 二叉树反转, 七行代码, 相比二行代码, 情有可原!   One solution (Cannot pass the phone interview - need to improve, show reasoning, logic…

链接: http://acm.hust.edu.cn/vjudge/contest/view.action?cid=88230#problem/C 求树的直径,这里只不过给每条边增加一个边长属性,变成了求树上两点距离最远为多少 树的直径,在今天比赛前我是没有接触过的, 队友说在学长的博客上看是用了两个bfs就可以了,可我看的题解是用了两个dfs 应该意思是一样的吧!!! 都学习一下 题解的代码: #include <cstdio> #include <cstring> #inclu…

题意: 给你一颗n-1条边的树,求某两点的最长路 思路: 随便找个根,然后我们从根往下搜,对于每个结点会出现多个子节点或者一个子节点或者没有结点, 多个子节点的话,就以他为中间点,在子节点中找两条最长的,加起来比比: 直接搜吧: 哎好难讲啊,其实画个图就很容易了:(直接注释在代码里面吧.. #include <bits/stdc++.h> using namespace std; typedef long long LL; const int N=3e4+10; struct Edge{ in…

提高自己的实力, 也为了证明, 开始板刷lightoj,每天题量>=1: 题目的类型会在这边说明,具体见分页博客: SUM=54; 1000 Greetings from LightOJ [简单A+B] 1001 Opposite Task  [简单题] 1002 Country Roads[搜索题] 1003 Drunk[判环] 1004 Monkey Banana Problem [基础DP] 1006 Hex-a-bonacci[记忆化搜索] 1008 Fibsieve`s Fantabu…

免费做一样新 1004 - Monkey Banana Problem 号码塔 1005 - Rooks 排列 1013 - Love Calculator LCS变形 dp[i][j][k]对于第一个字符串i 到jLCS为k的方案数 1068 - Investigation 数位dp 能被K整数且各位数字之和也能被K整除的数 dp[i][j][k] 到第i位每位数字之和的余数为j 当前数字余数为k 1079 - Just another Robbery 01背包 全部钱之和为背包体积 不被抓的…

Given the root of a complete binary tree, return the number of the nodes in the tree. According to Wikipedia, every level, except possibly the last, is completely filled in a complete binary tree, and all nodes in the last level are as far left as po…

Same Tree Given two binary trees, write a function to check if they are equal or not. Two binary trees are considered equal if they are structurally identical and the nodes have the same value. Maximum Depth of Binary Tree Given a binary tree, find i…

http://www.geeksforgeeks.org/lowest-common-ancestor-in-a-binary-search-tree/ Lowest Common Ancestor in a Binary Search Tree. Given values of two nodes in a Binary Search Tree, write a c program to find the Lowest Common Ancestor (LCA). You may assume…

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…

Given a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST. Top down 的解题方法: 1. 将LinkedList的值保存到一个数组中,转化成Convert Sorted Array to Binary Search Tree 来解决 时间复杂度为O(n), 空间复杂度为O(n) /** * Definition for singl…

题目如下:https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree/ 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 def…

variable point to code variable expression tree data structure lamda expression anonymous function 原文 Newcomers to LINQ often find expression trees difficult to grasp. In this post I hope to show that the subject is not quite as difficult as it might…

Apple Tree Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 9989   Accepted: 3324 Description Wshxzt is a lovely girl. She likes apple very much. One day HX takes her to an apple tree. There are N nodes in the tree. Each node has an amoun…

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…

Description Xenia the programmer has a tree consisting of n nodes. We will consider the tree nodes indexed from 1 to n. We will also consider the first node to be initially painted red, and the other nodes — to be painted blue. The distance between t…