8611 大牛之路I时间:2023-03-09 22:26:40 #include<stdio.h> int a[]; int main() { int i, n, m, sum, x, y; scanf("%d%d", &n, &m); for(i=; i<n; ++i) a[i] = i; for(i=; i<=m; ++i) { scanf("%d%d", &x, &y); a[y]=x; } for(sum=, i=; i<n; ++i) if(a[i] == i) ++sum; printf("%d\n", sum); }