并查集 & 最小生成树 并查集 Disjoint Sets 什么是并查集?     并查集,在一些有N个元素的集合应用问题中,我们通常是在开始时让每个元素构成一个单元素的集合,然后按一定顺序将属于同一组的元素所在的集合合并,其间要反复查找一个元素在哪个集合中.这一类问题近几年来反复出现在信息学的国际国内赛题中,其特点是看似并不复杂,但数据量极大,若用正常的数据结构来描述的话,往往在空间上过大,计算机无法承受:即使在空间上勉强通过,运行的时间复杂度也极高,根本就不可能在比赛规定的运行时间(1-3秒…

题目大意: 给一些没安排权值的边和安排了权值的边,没被安排的边全要被选入最小生成树,问你最大能把它们的权值和安排成多少.题目分析:假设建好了树,那么树边与剩下的每一条边都能构成一个环,并且非树边的权值是环中最大的,所以钦定边权不大于非树边即可.用并查集维护一下. 代码: #include<bits/stdc++.h> using namespace std; ; int n,k,m; struct edge{int from,to,w;}p1[maxn],p2[maxn]; int pre[m…

继续畅通工程 Time Limit:1000MS Memory Limit:32768KB 64bit IO Format:%I64d & %I64u Submit Status Description 省政府“畅通工程”的目标是使全省任何两个村庄间都可以实现公路交通(但不一定有直接的公路相连,只要能间接通过公路可达即可).现得到城镇道路统计表,表中列出了任意两城镇间修建道路的费用,以及该道路是否已经修通的状态.现请你编写程序,计算出全省畅通需要的最低成本. Input 测试输入包含若干测试用例…

Wireless Network Time Limit: 10000MS   Memory Limit: 65536K Total Submissions: 18066   Accepted: 7618 Description An earthquake takes place in Southeast Asia. The ACM (Asia Cooperated Medical team) have set up a wireless network with the lap computer…

A very big corporation is developing its corporative network. In the beginning each of the N enterprises of the corporation, numerated from 1 to N, organized its own computing and telecommunication center. Soon, for amelioration of the services, the…

Corporative Network Time Limit: 3000MS   Memory Limit: Unknown   64bit IO Format: %lld & %llu [Submit]   [Go Back]   [Status] Description   A very big corporation is developing its corporative network. In the beginning each of the N enterprises of th…

Description An earthquake takes place in Southeast Asia. The ACM (Asia Cooperated Medical team) have set up a wireless network with the lap computers, but an unexpected aftershock attacked, all computers in the network were all broken. The computers…

http://codeforces.com/problemset/problem/892/E 题意:给出一个 n 个点 m 条边的无向图,每条边有边权,共 Q 次询问,每次给出 ki​ 条边,问这些边能否同时在一棵最小生成树上. 这题乍一看看不出什么方法来,仔细一想发现除了确实看不出什么东西来. 但是我们从求最小生成树的kruskal算法里面可以发现,尽管一个图可以有多个最小生成树,但是想要把一条边替换掉领一条边变成最小生成树一定是两条边的权值相同. 所以说每一条权值不同的边是互相独立的,如果比…

An earthquake takes place in Southeast Asia. The ACM (Asia Cooperated Medical team) have set up a wireless network with the lap computers, but an unexpected aftershock attacked, all computers in the network were all broken. The computers are repaired…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=1863 畅通工程 Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 17593    Accepted Submission(s): 7417 Problem Description 省政府“畅通工程”的目标是使全省任何两个村庄间都可以实现公路交…