Submission #567171

#	Time	Username	Problem	Language	Result	Execution time	Memory
567171		Mahdi	Duathlon (APIO18_duathlon)	C++17	23 / 100	89 ms	18412 KiB

count_triplets

#include<bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
#define all(v) v.begin(), v.end()
#define F first
#define S second
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<int, ll>pil;
const int N=1e5+5;
int n, m, sz[N], nn;
vector<int>g[N], nd, kd[N];
bool mk[N];

void dfs(const int &v){
    mk[v]=1;
    sz[v]=1;
    nd.push_back(v);
    for(int u: g[v]){
        if(!mk[u]){
            kd[v].push_back(u);
            dfs(u);
            sz[v]+=sz[u];
        }
    }
}

int main(){
    ios_base::sync_with_stdio(0); cin.tie(0);
    cin>>n>>m;
    if(m>=n)
        return 0;
    for(int i=0;i<m;++i){
        int u, v;
        cin>>u>>v;
        g[--u].push_back(--v);
        g[v].push_back(u);
    }
    ll ans=0;
    for(int i=0;i<n;++i){
        if(!mk[i]){
            dfs(i);
            for(int v: nd){
                nn=nd.size();
                ans+=1LL*(nn-1)*(nn-2);
                ans-=1LL*(nn-sz[v])*(nn-sz[v]-1);
                for(int u: kd[v])
                    ans-=1LL*sz[u]*(sz[u]-1);
            }
            nd.clear();
        }
    }
    cout<<ans<<'\n';
}

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