目录 @description@ @solution@ @accepted code@ @details@ @description@ 给定一个竞赛图(有向完全图),请找出里面的某个三元环,或者判断不存在这样的环. Input 第一行包含一个整数 n (1 ≤ n ≤ 5000). 接下来 n 行包含这个图的邻接矩阵,其中 A[i, j] = 1 表示存在一条 i 到 j 的边. 保证 A[i, i] = 0, A[i, j] ≠ A[j, i] (1 ≤ i, j ≤ n, i ≠ j). O…

A tournament is a directed graph without self-loops in which every pair of vertexes is connected by exactly one directed edge. That is, for any two vertexes u and v (u ≠ v) exists either an edge going from u to v, or an edge from v to u. You are give…

D. Vitaly and Cycle Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/557/problem/D Description After Vitaly was expelled from the university, he became interested in the graph theory. Vitaly especially liked the cycles of an…

题目链接:http://codeforces.com/problemset/problem/117/C C. Cycle time limit per test 2.5 seconds memory limit per test 256 megabytes input standard input output standard output A tournament is a directed graph without self-loops in which every pair of ve…

time limit per test1 second memory limit per test256 megabytes inputstandard input outputstandard output After Vitaly was expelled from the university, he became interested in the graph theory. Vitaly especially liked the cycles of an odd length in w…

[Codeforces 1205B]Shortest Cycle(最小环) 题面 给出n个正整数\(a_i\),若\(a_i \& a_j \neq 0\),则连边\((i,j)\)(注意i->j的边和j->i的边看作一条.问连边完图的最小环长度 \(n \leq 10^5,0 \leq a_i \leq 10^{18}\) 分析 我们按位考虑.显然满足第i位为1的所有数两两之间都有边,构成一个完全图. 统计第i位为1的数,如果第i位为1的数超过2个,就直接输出3(这3个构成一个最小环…

题目连接:http://codeforces.com/contest/962/problem/F 题目大意是定义一个simple cycle为从一个节点开始绕环走一遍能经过simple cycle内任何一个节点,并且不超过一次. 因为是无向图,而且是环,即为连通分量,所以模型转化为求点双连通分量,依据题意求得的点双连通分量需要满足题目simple cycle的定义,所以当一个点双连通分量的边数量和点数量相等时才能构成simple cycle,在tarjan求割点的时候,需要存储点双联通分量的点和…

题目链接:http://codeforces.com/problemset/problem/263/D 思路:一遍dfs即可,dp[u]表示当前遍历到节点u的长度,对于节点u的邻接点v,如果v没有被访问过,则继续访问,否则计算dp[u] - dp[v] + 1是否大于等于K + 1,如果是,就说明找到了这样一个符合要求的环,然后将回退,回退的时候将环上的节点标记即可,否则,就继续找. #include <iostream> #include <cstdio> #include &l…

D. Vitaly and Cycle       time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output After Vitaly was expelled from the university, he became interested in the graph theory. Vitaly especially liked th…

题目链接: 点这里 题目 D. Vitaly and Cycle time limit per test1 second memory limit per test256 megabytes inputstandard input outputstandard output 问题描述 After Vitaly was expelled from the university, he became interested in the graph theory. Vitaly especially…