Rikka with Graph Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others) Total Submission(s): 190    Accepted Submission(s): 78 Problem Description As we know, Rikka is poor at math. Yuta is worrying about this situation,…

n个点最少要n-1条边才能连通,可以删除一条边,最多删除2条边,然后枚举删除的1条边或2条边,用并查集判断是否连通,时间复杂度为O(n^3) 这边犯了个错误, for(int i=0;i<N;i++){ fa[i]=i; } 这个将i<=N,导致错误,值得注意 AC代码: #pragma comment(linker, "/STACK:1024000000,1024000000") #include<iostream> #include<cstdio>…

Rikka with Graph 题目连接: http://acm.hdu.edu.cn/showproblem.php?pid=5631 Description As we know, Rikka is poor at math. Yuta is worrying about this situation, so he gives Rikka some math tasks to practice. There is one of them: Yuta has a non-direct gra…

Rikka with Graph  Accepts: 123  Submissions: 525  Time Limit: 2000/1000 MS (Java/Others)  Memory Limit: 65536/65536 K (Java/Others) 问题描述 众所周知,萌萌哒六花不擅长数学,所以勇太给了她一些数学问题做练习,其中有一道是这样的: 给出一张 nn 个点 n+1n+1 条边的无向图,你可以选择一些边(至少一条)删除. 现在勇太想知道有多少种方案使得删除之后图依然联通.…

Rikka with Graph Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others) Total Submission(s): 182    Accepted Submission(s): 95 Problem Description As we know, Rikka is poor at math. Yuta is worrying about this situation,…

/** problem: http://poj.org/problem?id=3177 tarjan blog: https://blog.csdn.net/reverie_mjp/article/details/51704523 v 为下一结点, u为当前结点 如果low[v] > dfn[u] 则 边(u,v)为桥 缩点后剩下的所有边都为桥(缩点后即为树结构) 将叶子结点相连使其成为双联通分量为最优解 所以: 添加(leaf + 1) / 2 条边即可使图成为双联通图 **/ #includ…

Tarjan算法就不说了 想学看这 https://www.byvoid.com/blog/scc-tarjan/ https://www.byvoid.com/blog/biconnect/ 下面是几份基本的模版 首先是无向图割点桥的代码 下面的代码是用于求割点数目的 其中add_block[u] = x  表示删除u点之后增加的联通块个数.注意是增加的联通块个数 ; ; const int INF = 0x3f3f3f3f; struct Edge { int u,v,next; int w…

题目:给定一张n个点m条有权边的无向联通图,q次询问两点间的最短路 n≤100000,m≤100000,m-n≤20. 首先看到m-n≤20这条限制,我们可以想到是围绕这个20来做这道题. 即如果我们随便在图上找一棵树,有最多21条非树边,连接最多42个顶点 考虑两点x,yx,y之间的最短路就是某个点到xx和yy的最短路之和 首先对于只走树边的情况,这个点是两点的LCA 如果经过非树边,xx或yy到枚举的这个点的最短路上的最后一条边一定是非树边(如果都是树边的话完全可以转化到一个连接着非树边的点…

Rikka with Graph II Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 1051    Accepted Submission(s): 266 Problem Description As we know, Rikka is poor at math. Yuta is worrying about this situati…

Rikka with Graph Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others) Problem Description As we know, Rikka is poor at math. Yuta is worrying about this situation, so he gives Rikka some math tasks to practice. There is…