View difference between Paste ID: eLxLVae9 and nRY7BeuA

 #include <bits/stdc++.h>
 
 using namespace std;
 
 int n, m, a, b, s, k;
 vector<vector<int> > lef;
 vector<int> righ;
 vector<int> used;
 
 bool dfs(int now) {
     if (used[now] == 1) {
         return false;
     }
     used[now] = 1;
     for (auto j : lef[now]) {
         if (righ[j] == -1 || dfs(righ[j])) {
             righ[j] = now;
             return true;
         }
     }
     return false;
 }
 
 int main() {
     cin >> n >> m >> k;
     lef.resize(n);
     righ.resize(m, -1);
     used.resize(n);
     for (int i = 0; i < k; i++) {
         cin >> a >> b;
         lef[a - 1].push_back(b - 1);
     }
     for (int i = 0; i < n; i++) {
         fill(used.begin(), used.end(), 0);
         dfs(i);
     }
     long long ans = 0;
     for (int i = 0; i < m; i++) {
         if (righ[i] != -1) {
             ans++;
         }
     }
     cout << ans << endl;
     return 0;
 }