#include using namespace std; #define inf 0x3f3f3f3f const int N = 510; int n, m, x, y, ans; int g[N][N]; void floyd() { for (int k = 1; k <= n; k++) for (int i = 1; i <= n; i++) { if (!g[i][k]) continue; // floyd优化 for (int j = 1; j <= n; j++) g[i][j] |= g[i][k] & g[k][j]; // 通过k传递,或运算 } } int main() { int T; cin >> T; while (T--) { cin >> n >> m; memset(g, 0, sizeof g); while (m--) { cin >> x >> y; g[x][y] = 1; // x