Submission #790344

#	Time	Username	Problem	Language	Result	Execution time	Memory
790344		Dan4Life	Duathlon (APIO18_duathlon)	C++17	8 / 100	86 ms	12124 KiB

count_triplets

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pb push_back
#define sz(a) (int)a.size()
#define all(a) begin(a),end(a)
using ar = array<int,2>;
const int mxN = (int)1e5+10;
int n, m, ans, vis[mxN];
vector<int> v, adj[mxN];

void dfs(int s){
	vis[s]=1; v.pb(s);
	for(auto u : adj[s])
		if(!vis[u]) dfs(u);
}

int32_t main() {
	cin >> n >> m;
	for(int i = 0; i < m; i++){
		int a, b; cin >> a >> b;
		adj[a].pb(b), adj[b].pb(a);
	}
	for(int i = 1; i <= n; i++){
		if(vis[i]) continue;
		v.clear(); dfs(i); 
		bool ok = 1; int x = sz(v);
		for(auto u : v) ok&=sz(adj[u])==2;
		if(ok) ans+=x*(x-1)*(x-2);
		else ans+= (x*(x-1)*(x-2))/3;
	}
	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