Submission #203728

#	Time	Username	Problem	Language	Result	Execution time	Memory
203728		Segtree	Duathlon (APIO18_duathlon)	C++14	8 / 100	145 ms	10232 KiB

count_triplets

#include<iostream>
#include<algorithm>
#include<vector>
#include<set>
using namespace std;
typedef long long ll;
typedef pair<ll,ll> P;
#define rep(i,n) for(int i=0;i<n;i++)
#define chmin(a,b) a=min(a,b)
#define chmax(a,b) a=max(a,b)
#define N 100010
ll n,m;
vector<ll> g[N];
ll vcnt,ecnt;
bool vis[N];
void dfs(ll x){
	if(vis[x])return;
	vis[x]=1; vcnt++;
	for(auto y:g[x]){
		ecnt++;
		dfs(y);
	}
}
int main(){
	ll n,m; cin>>n>>m;
	rep(i,m){
		ll a,b; cin>>a>>b;
		a--,b--;
		g[a].push_back(b);
		g[b].push_back(a);
	}
	ll ans=0;
	rep(i,n)vis[i]=0;
	rep(i,n){
		if(vis[i]==0){
			vcnt=ecnt=0;
			dfs(i);
			ecnt/=2;
			if(ecnt==vcnt-1)ans+=vcnt*(vcnt-1)*(vcnt-2)/3;
			else ans+=vcnt*(vcnt-1)*(vcnt-2);
		}
	}
	cout<<ans<<endl;
}

• 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