Submission #277121

#	Time	Username	Problem	Language	Result	Execution time	Memory
277121		tinjyu	Duathlon (APIO18_duathlon)	C++14	23 / 100	1112 ms	1048580 KiB

count_triplets

#include <iostream>
using namespace std;
long long int cnt,tag[100005],son[1000005],ans,tmp[1000005],n,m,road[1000005],map[1000005][2];
void dfs(int x,int fa)
{
	tag[x]=1;
	son[x]=1;
	cnt++;
	long long int g=road[x];
	while(g!=-1)
	{
		long long int now=map[g][0];
		if(now!=fa)
		{
			dfs(now,x);
			son[x]+=son[now];
		}
		g=map[g][1];
	}
	return ;
}
void find(int x,int fa)
{
	long long int g=road[x];
	while(g!=-1)
	{
		long long int now=map[g][0];
		if(now!=fa)
		{
			ans+=(cnt-son[now]-1)*son[now];
		}
		g=map[g][1];
	}
	ans+=(cnt-son[x])*(son[x]-1);
	g=road[x];
	while(g!=-1)
	{
		long long int now=map[g][0];
		if(now!=fa)
		{
			find(now,x);
		}
		g=map[g][1];
	}
	return ;
}
int main(){
	cin>>n>>m;
	for(int i=1;i<=n;i++)road[i]=-1;
	for(int i=1;i<=m;i++)
	{
		int u,v;
		cin>>u>>v;
		map[i*2][0]=v;
		map[i*2][1]=road[u];
		road[u]=i*2;
		map[i*2+1][0]=u;
		map[i*2+1][1]=road[v];
		road[v]=i*2+1;
	}
	for(int i=1;i<=n;i++)
	{
		if(tag[i]==0)
		{
			cnt=0;
			dfs(i,-1);
			find(i,-1);
			//cout<<i<<" "<<ans<<endl;
		}
	}
	cout<<ans<<endl;
	return 0;
}

• 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