Submission #821195

#	Time	Username	Problem	Language	Result	Execution time	Memory
821195		DobromirAngelov	Marshmallow Molecules (CCO19_day2problem2)	C++17	5 / 25	35 ms	5964 KiB

Main

#include<bits/stdc++.h>
#define endl '\n'

using namespace std;

const int MAXN=1e5+5;

int n,m;
vector<int> adj[MAXN];
bool used[MAXN];
long long ans=0;

void solve(int v)
{
    used[v]=1;
    priority_queue<int> pq;
    pq.push(-v);
    while(!pq.empty())
    {
        v=-pq.top();
        pq.pop();
        int bef=pq.size();
        int br=0;
        for(int i=0;i<adj[v].size();i++)
        {
            if(!used[adj[v][i]])
            {
                used[adj[v][i]]=1;
                pq.push(-adj[v][i]);
                br++;
            }
        }
        ans+=br;
        ans+=(long long) br*bef;
        ans+=(long long) br*(br-1)/2;
    }
}

int main()
{
ios::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);

cin>>n>>m;
for(int i=0;i<m;i++)
{
    int u,v;
    cin>>u>>v;
    adj[u].push_back(v);
}

for(int i=1;i<=n;i++)
{
    if(!used[i])
    {
        if(adj[i].size()==0) continue;
        solve(i);
    }
}

cout<<ans<<endl;

return 0;
}

Compilation message (stderr)

Main.cpp: In function 'void solve(int)':
Main.cpp:24:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   24 |         for(int i=0;i<adj[v].size();i++)
      |                     ~^~~~~~~~~~~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 5
• Subtask 3: 5 / 5
• Subtask 4: 0 / 10