题意:给出n个点的坐标,要把n个点连通,使得总距离最小,可是有m对点已经连接,输入m,和m组a和b,表示a和b两点已经连接. 思路:两种做法.(1)用prim算法时,输入a,b.令mp[a][b]=0.然后进行一遍prim(2)Kruskal算法+并查集 代码: //prim写法 #include <iostream> #include <cstdio> #include <cstring> #include <algorithm> #include <…

开始了最小生成树,以简单应用为例hoj1323,1232(求连通分支数,直接并查集即可) prim(n*n) 一般用于稠密图,而Kruskal(m*log(m))用于系稀疏图 #include<iostream> //prim n^2 #include<cstdio> #include<cstring> using namespace std; const int inf=0x3f3f3f3f; int a[102][102];int dis[102];int mark…

描述 You have n computers numbered from 1 to n and you want to connect them to make a small local area network (LAN). All connections are two-way (that is connecting computers i and j is the same as connecting computers j and i). The cost of connecting…

UVA 11987 - Almost Union-Find 题目链接 题意:给定一些集合,操作1是合并集合,操作2是把集合中一个元素移动到还有一个集合,操作3输出集合的个数和总和 思路:并查集,关键在于操作2,对于并查集,要去除掉一个结点,假设该结点不是根那就好办了,那么就多开n个结点,每一个结点初始父亲都是它的i + n,这样在移动的时候,就不用操心他是根结点了剩下就是普通的带权并查集了 代码: #include <cstdio> #include <cstring> const…

畅通工程 Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 34605    Accepted Submission(s): 15333 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).经过调查评估,得到的统计表中列…

Conscription Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 14661   Accepted: 5102 Description Windy has a country, and he wants to build an army to protect his country. He has picked up N girls and M boys and wants to collect them to b…

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 \(k\)条边,问这些边能否同时在一棵最小生成树上. Solution 所有最小生成树中某权值的边的数量是一定的 加完小于某权值的所有边后图的连通性是一样的 对于每个询问,每种权值分开考虑 对每个权值,加完小于这条边的权值后的所有边 然后判断这个权值在缩点后图上是否成环 因此需要跑一次 Kruskal 并且记录下对于每条边,加完权值小于它的所有边后,其两个端点所在的连通块编号 这样询问时只需要拿着并查集搞就可以了 #inc…

https://vjudge.net/problem/UVA-1395 题意: 给出一个n结点的图,求苗条度(最大边减最小边的值)尽量小的生成树. 思路: 主要还是克鲁斯卡尔算法,先仍是按权值排序,对于一个连续的边集区间[L,R],如果这些边使得n个点全部连通,则一定存在一个苗条度不超过W[R]-W[L]的生成树.从小到大枚举L,对于每个L,从小到大枚举R. 这道题目我一直超时,最后发现数组开小了,我一直以为数组开小了肯定会出来Runtime error的... #include<iostrea…

Building a Space Station Time Limit: 1000MS   Memory Limit: 30000K Total Submissions: 7469   Accepted: 3620 Description You are a member of the space station engineering team, and are assigned a task in the construction process of the station. You ar…

Jungle Roads Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 23882   Accepted: 11193 Description The Head Elder of the tropical island of Lagrishan has a problem. A burst of foreign aid money was spent on extra roads between villages som…