H - Cow Contest

 1 #include <iostream>
 2 #include <algorithm>
 3 #include <string>
 4 #include <cstring>
 5 using namespace std;
 6 
 7 int n, m;
 8 const int maxn = 105;
 9 int mp[maxn][maxn];
10 
11 int main(){
12     ios_base::sync_with_stdio(false);
13     cin.tie(0);
14     memset(mp, 0, sizeof(mp));
15     cin >> n >> m;
16     for(int i = 0;i < m;i++){
17         int  x, y;
18         cin >> x >> y;
19         mp[x][y] = 1;
20         mp[y][x] = -1;
21     }
22 
23     for(int i = 1;i <= n;i++){
24         for(int j = 1;j <= n;j++){
25             for(int k = 1;k <= n;k++){
26                 if(mp[j][i] == mp[i][k] && mp[j][i] != 0){
27                     mp[j][k] = mp[j][i];
28                 }
29             }
30         }
31     }
32     int ans = 0;
33     for(int i = 1;i <= n;i++){
34         int sum = 0;
35         for(int j = 1;j <= n;j++){
36             if(mp[i][j] != 0){
37                 sum++;
38             }
39         }
40         if(sum == n-1){
41             ans++;
42         }
43     }
44     cout << ans << endl;
45 
46     return 0;
47 }