Triangle LOVE
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Others)
Total Submission(s): 2271 Accepted Submission(s): 946
Problem Description Recently, scientists find that there is love between any of two people. For example, between A and B, if A don’t love B, then B must love A, vice versa. And there is no possibility that two people love each other, what a crazy world!
Now, scientists want to know whether or not there is a “Triangle Love” among N people. “Triangle Love” means that among any three people (A,B and C) , A loves B, B loves C and C loves A.
Your problem is writing a program to read the relationship among N people firstly, and return whether or not there is a “Triangle Love”.
Input The first line contains a single integer t (1 <= t <= 15), the number of test cases.
For each case, the first line contains one integer N (0 < N <= 2000).
In the next N lines contain the adjacency matrix A of the relationship (without spaces). A
i,j = 1 means i-th people loves j-th people, otherwise A
i,j = 0.
It is guaranteed that the given relationship is a tournament, that is, A
i,i= 0, A
i,j ≠ A
j,i(1<=i, j<=n,i≠j).
Output For each case, output the case number as shown and then print “Yes”, if there is a “Triangle Love” among these N people, otherwise print “No”.
Take the sample output for more details.
Sample Input
2
5
00100
10000
01001
11101
11000
5
01111
00000
01000
01100
01110
Sample Output
Case #1: Yes
Case #2: No
题意:给你一个特殊的有向图,该有向图的任意两个节点u与v之间有且仅有一条单向边,现在问你该有向图是否存在由3个节点构成的环.
该图本质是拓扑排序题.如果该图可以拓扑排序,那么不存在3节点的环,否则存在3节点的环.
#include
#include
#include
#include
#include
#include
using namespace std; const int M = 2000 + 5; int n; int in[M]; char str[M]; int t; vector
map[M]; bool toposort() { int sum = 0; queue
Q; for(int i=0; i
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