제출 #287318

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
287318		ScarletS	철인 이종 경기 (APIO18_duathlon)	C++17	23 / 100	1160 ms	1048580 KiB

count_triplets

#include <bits/stdc++.h>
#define ll long long
#define sz(x) (int)(x).size()
using namespace std;

const int MAXN = 1e5 + 7;
vector<int> edges[MAXN];
ll subTree[MAXN];
bool done[MAXN];
vector<int> cur;
ll ans=0;

void dfs(int c, int p)
{
	done[c]=1;
	cur.push_back(c);
	subTree[c]=1;
	for (int i : edges[c])
		if (i!=p)
		{
			dfs(i,c);
			ans+=(subTree[i]*(subTree[c]-1));
			//cout<<ans<<" "<<i<<" "<<c<<"\n";
			subTree[c]+=subTree[i];
		}
}

int main()
{
	int n,m,u,v;
	cin>>n>>m;
	while (m--)
	{
		cin>>u>>v;
		edges[u].push_back(v);
		edges[v].push_back(u);
	}
	for (int i=1;i<=n;++i)
		if (!done[i])
		{
			cur.clear();
			dfs(i,0);
			//cout<<ans<<"\n";
			for (int j : cur)
				ans+=((subTree[i]-subTree[j])*(subTree[j]-1));
		}
	cout<<(ans<<1);
}

• 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