제출 #744453

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
744453		Abito	철인 이종 경기 (APIO18_duathlon)	C++14	0 / 100	1087 ms	1048576 KiB

count_triplets

#include <bits/stdc++.h>
#define pb push_back
#define F first
#define S second
#define endl '\n'
#define ep insert
#define pow pwr
#define sqrt sqrtt
#define elif else if
#define y1 YONE
#define int long long
using namespace std;
const int N=1e6+5;
int n,m,sz[N],par[N];
vector<int> adj[N];
int getsize(int node,int p){
    par[node]=p;
    sz[node]=1;
    for (auto u:adj[node]){
        if (u==p) continue;
        sz[node]+=getsize(u,node);
    }return sz[node];
}
int32_t main(){
    ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
    cin>>n>>m;
    for (int i=1;i<=m;i++){
        int x,y;
        cin>>x>>y;
        adj[x].pb(y);
        adj[y].pb(x);
    }
    getsize(1,0);
    int ans=0;
    for (int i=1;i<=n;i++){
        int x=sz[i]-1;
        for (auto u:adj[i]){
            if (u==par[i]) continue;
            x-=sz[u];
            ans+=x*sz[u];
        }ans+=(n-sz[i])*(sz[i]-1);
    }
    cout<<ans*2LL<<endl;
    return 0;
}

• 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