Submission #567182

#	Time	Username	Problem	Language	Result	Execution time	Memory
567182		Mahdi	Duathlon (APIO18_duathlon)	C++17	8 / 100	63 ms	10228 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, nn;
vector<int>g[N], nd;
bool mk[N];

void dfs(const int &v){
    mk[v]=1;
    nd.push_back(v);
    for(int u: g[v]){
        if(!mk[u])
            dfs(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);
            nn=nd.size();
            bool b=1;
            for(int v: nd){
                if(g[v].size()==1){
                    b=0;
                    break;
                }
            }
            if(b)
                ans+=1LL*nn*(nn-1)*(nn-2);
            else
                ans+=1LL*nn*(nn-1)*(nn-2)/3;
            nd.clear();
        }
    }
    cout<<ans<<'\n';
}

• 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