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  1. #include <bits/stdc++.h>
  2. #define int long long
  3.  
  4. using namespace std;
  5.  
  6. int n, m;
  7. vector<int> adj[51];
  8. int visited[51];
  9.  
  10. int BFS(int s) {
  11.     int cnt = 1;
  12.     queue<int> q;
  13.  
  14.     q.push(s);
  15.     visited[s] = true;
  16.  
  17.     while (!q.empty()) {
  18.         int u = q.front();
  19.         q.pop();
  20.  
  21.         for (int v : adj[u]) {
  22.             if (!visited[v]) {
  23.                 cnt += 1;
  24.                 q.push(v);
  25.                 visited[v] = true;
  26.             }
  27.         }
  28.     }
  29.  
  30.     return cnt;
  31. }
  32.  
  33. int32_t main() {
  34.     ios_base::sync_with_stdio(false);
  35.     cin.tie(NULL);
  36.  
  37.     cin >> n >> m;
  38.  
  39.     int res = 1;
  40.  
  41.     for (int i = 1, x, y; i <= m; i += 1) {
  42.         cin >> x >> y;
  43.         adj[x].push_back(y);
  44.         adj[y].push_back(x);
  45.     }
  46.  
  47.     for (int i = 1; i <= n; i += 1) {
  48.         if (!visited[i]) {
  49.             int Size = BFS(i);
  50.             for (int k = 1; k < Size; k += 1) {
  51.                 res *= 2;
  52.             }
  53.         }
  54.     }
  55.  
  56.     cout << res;
  57.  
  58.     return 0;
  59. }
  60.  
Success #stdin #stdout 0s 5288KB
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https://ideone.com/M3xT8W
language:
C++14 (gcc 8.3)
created:
4 days ago
visibility:
public

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