Submission #701512

#	Time	Username	Problem	Language	Result	Execution time	Memory
701512		Abrar_Al_Samit	Duathlon (APIO18_duathlon)	C++17	0 / 100	446 ms	1048576 KiB

count_triplets

#include<bits/stdc++.h>
using namespace std;

const int nax = 1002;

vector<int>g[nax];
int n, m;
long long ans = 0;
bool vis[nax];
int sub[nax];

int dfs1(int v, int p) {
  sub[v] = 1;
  vis[v] = 1;
  for(int u : g[v]) if(u!=p) {
    sub[v] += dfs1(u, v);
  }
  return sub[v];
}
void dfs2(int v,int p, int anc) {
  for(int i=0; i<g[v].size(); ++i) if(g[v][i]!=p) {
    dfs2(g[v][i], v, anc+1);
    for(int j=i+1; j<g[v].size(); ++j) if(g[v][j]!=p) {
      ans += sub[g[v][i]] * 1LL * sub[g[v][j]];
    }
  }
  ans += (sub[v]-1) * 1LL * anc;
}
void PlayGround() {
  cin>>n>>m;
  for(int i=0; i<m; ++i) {
    int u, v;
    cin>>u>>v;
    g[u].push_back(v);
    g[v].push_back(u);
  }

  for(int i=1; i<=n; ++i) if(!vis[i]) {
    dfs1(i, i);
    dfs2(i, i, 0);
  }
  cout<<ans*2<<'\n';

  // cerr << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n";
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  PlayGround();
  return 0;
}

Compilation message (stderr)

count_triplets.cpp: In function 'void dfs2(int, int, int)':
count_triplets.cpp:21:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |   for(int i=0; i<g[v].size(); ++i) if(g[v][i]!=p) {
      |                ~^~~~~~~~~~~~
count_triplets.cpp:23:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   23 |     for(int j=i+1; j<g[v].size(); ++j) if(g[v][j]!=p) {
      |                    ~^~~~~~~~~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 11
• Subtask 3: 0 / 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