Submission #387672

#	Time	Username	Problem	Language	Result	Execution time	Memory
387672		milleniumEeee	Duathlon (APIO18_duathlon)	C++17	5 / 100	1095 ms	11764 KiB

count_triplets

#include <bits/stdc++.h>
#define fastInp ios_base::sync_with_stdio(0); cin.tie(0);
#define pii pair<int, int>
#define fr first
#define sc second
#define pb push_back
#define szof(s) (int)s.size()
#define all(s) s.begin(), s.end()
#define mk make_pair
using namespace std;

const int MAXN = (int)1e5 + 5;
vector <int> g[MAXN];

int S, C, F;

bool used[MAXN];

bool dfs(int v) {
	used[v] = 1;
	if (v == F) {
		used[v] = 0;
		if (!used[C]) {
			return false;
		} else {
			return true;
		}
	}
	bool found = false;
	for (int to : g[v]) {
		if (!used[to]) {
			found |= dfs(to);
			if (found) {
				used[v] = 0;
				return true;
			}
		}
	}
	used[v] = 0;
	return false;
}

signed main() {
	fastInp;
	int n, m;
	cin >> n >> m;
	for (int i = 1; i <= m; i++) {
		int u, v;
		cin >> u >> v;
		g[u].pb(v);
		g[v].pb(u);
	}
	int ans = 0;
	for (int s = 1; s <= n; s++) {
		for (int c = 1; c <= n; c++) {
			for (int f = 1; f <= n; f++) {
				if (s != c && s != f && c != f) {
					S = s;
					C = c;
					F = f;
					if (dfs(s)) {
						ans++;
					}
				}
			}
		}
	}
	cout << ans << endl;
}

/*
4 3 
1 2
2 3
3 4
*/

• Subtask 1: 5 / 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