1 /* 2 Name:nyoj-211-Cow Contest 3 Copyright: 4 Author: 5 Date: 2018/4/27 21:02:06 6 Description: 7 floyd算法 8 大佬的惊奇思路 9 */10 #include11 #include 12 #include 13 using namespace std;14 15 const int MAXN = 105;16 const int INF = 0x3f3f3f3f;17 int N, g[MAXN][MAXN], M;18 19 void floyd() {20 for (int k=1; k<=N; k++) {21 for (int i=1; i<=N; i++) {22 for (int j=1; j<=N; j++) {23 if (g[i][k] && g[k][j])24 g[i][j] = 1;//有关系 25 }26 }27 }28 }29 int main()30 {31 while (cin>>N>>M, N+M) {32 memset(g, 0, sizeof(g));33 for (int i=0; i >x>>y;36 g[x][y] = 1;37 }38 floyd();39 int i, j, ans=0;40 for (i=1; i<=N; i++) {41 for (j=1; j<=N; j++) {42 if (i==j) continue;43 if (g[i][j] == 0 && g[j][i] == 0) break;//和其他牛中的一头没有关系就不能确定排名 44 }45 if (j > N) ans++;46 }47 cout< <