Submission #569110

#	Time	Username	Problem	Language	Result	Execution time	Memory
569110		SSRS	Duathlon (APIO18_duathlon)	C++14	8 / 100	109 ms	5956 KiB

count_triplets

#include <bits/stdc++.h>
using namespace std;
int main(){
  int n, m;
  cin >> n >> m;
  vector<vector<int>> E(n);
  for (int i = 0; i < m; i++){
    int u, v;
    cin >> u >> v;
    u--;
    v--;
    E[u].push_back(v);
    E[v].push_back(u);
  }
  vector<bool> used(n, false);
  long long ans = 0;
  for (int i = 0; i < n; i++){
    if (!used[i]){
      used[i] = true;
      int cntv = 0, cnte = 0;
      queue<int> Q;
      Q.push(i);
      while (!Q.empty()){
        int v = Q.front();
        Q.pop();
        cntv++;
        cnte += E[v].size();
        for (int w : E[v]){
          if (!used[w]){
            used[w] = true;
            Q.push(w);
          }
        }
      }
      cnte /= 2;
      if (cnte == cntv - 1){
        ans += (long long) cntv * (cntv - 1) * (cntv - 2) / 3;
      } else {
        ans += (long long) cntv * (cntv - 1) * (cntv - 2);
      }
    }
  }
  cout << ans << endl;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 11
• Subtask 3: 8 / 8
• Subtask 4: 0 / 10
• Subtask 5: 0 / 13
• Subtask 6: 0 / 15
• Subtask 7: 0 / 20
• Subtask 8: 0 / 8
• Subtask 9: 0 / 10