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  1. #include <bits/stdc++.h>
  2.  
  3. #define ll long long
  4. #define el cout << '\n'
  5. #define ii pair<int, int>
  6. #define fi first
  7. #define se second
  8.  
  9. using namespace std;
  10.  
  11. const int maxn = 255;
  12. const int INF = 1e9;
  13.  
  14. int n, m, d[maxn + 10][maxn + 10], s, t;
  15. vector<int> adj[maxn + 10];
  16. bool vis[maxn + 10][maxn + 10];
  17.  
  18. int main()
  19. {
  20.     ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  21.     if (fopen("BAGENTS.INP", "r"))
  22.     {
  23.         freopen("BAGENTS.INP", "r", stdin);
  24.         freopen("BAGENTS.OUT", "w", stdout);
  25.     }
  26.  
  27.     cin >> n >> m;
  28.     cin >> s >> t;
  29.     for (int i = 1; i <= m; i++)
  30.     {
  31.         int x, y;
  32.         cin >> x >> y;
  33.         adj[x].push_back(y);
  34.     }
  35.     d[s][t] = 0;
  36.     vis[s][t] = 1;
  37.     queue<ii> q;
  38.     q.push({s, t});
  39.  
  40.     while (!q.empty())
  41.     {
  42.         ii t = q.front();
  43.         q.pop();
  44.         int x = t.fi;
  45.         int y = t.se;
  46.  
  47.         if (x == y) return cout << d[x][y], 0;
  48.  
  49.         for (int next_x : adj[x])
  50.             for (int next_y : adj[y])
  51.             {
  52.                 if (vis[next_x][next_y]) continue;
  53.                 d[next_x][next_y] = d[x][y] + 1;
  54.                 vis[next_x][next_y] = 1;
  55.                 q.push({next_x, next_y});
  56.             }
  57.     }
  58.     cout << -1;
  59. }
  60.  
Success #stdin #stdout 0s 5280KB
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https://ideone.com/7FsPzf
language:
C++14 (gcc 8.3)
created:
9 days ago
visibility:
public

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