Submission #1207580

#	Time	Username	Problem	Language	Result	Execution time	Memory
1207580		madamadam3	Duathlon (APIO18_duathlon)	C++20	5 / 100	1096 ms	11332 KiB

count_triplets

#include <bits/stdc++.h>

using namespace std;

#define int long long int

const int MAXN = 100'001, MAXM = 200'001;
int n, m;

vector<int> adj[MAXN];
int sz[MAXN], tin[MAXN], low[MAXN], par[MAXN];
bool vis[MAXN];

bool dfs(int u1, int u2, vector<bool> &vis, int target) {
    if (u1 == target && u2 == target) {
        return true;
    }

    if (u1 != target) vis[u1] = true;
    if (u2 != target) vis[u2] = true;

    if (u1 == target && u2 != target) {
        for (int v2 : adj[u2]) {
            if (vis[v2]) continue;
            if (dfs(u1, v2, vis, target)) return true;
        }
    } else if (u1 != target && u2 == target) {
        for (int v1 : adj[u1]) {
            if (vis[v1]) continue;
            if (dfs(v1, u2, vis, target)) return true;
        }
    } else {
        for (int v1 : adj[u1]) {
            if (vis[v1]) continue;
            for (int v2 : adj[u2]) {
                if (vis[v2]) continue;
                if (v1 == v2 && v1 != target) continue;
                if (dfs(v1, v2, vis, target)) return true;
            }
        }
    }

    if (u1 != target) vis[u1] = false;
    if (u2 != target) vis[u2] = false;

    return false;
}

signed main() {
    cin >> n >> m;
    for (int i = 0; i < m; i++) {
        int u, v; cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }

    int ways = 0;
    for (int s = 1; s <= n; s++) {
        for (int c = 1; c <= n; c++) {
            if (c == s) continue;
            for (int f = 1; f <= n; f++) {
                if (f == c || f == s) continue;
                vector<bool> vis(n+1, false);
                if (dfs(s, f, vis, c)) {
                    ways++;
                    // cout << "(" << s << ", " << c << ", " << f << ") works\n";
                }
            }
        }
    }
    
    cout << ways;
    return 0;
}

• 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