백준 13023

www.acmicpc.net/problem/13023

13023번: ABCDE

#include <iostream>
#include <vector>
using namespace std;
int n, m, a, b, visited[2001];
vector<vector<int> > v;
void dfs(int idx, int cnt) {
    if (cnt == 5) {
        cout << 1;
        exit(0);
    }
    for (int i : v[idx]) {
        if (!visited[i]) {
            visited[i] = 1;
            dfs(i, cnt+1);
            visited[i] = 0;
        }
    }
}
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin >> n >> m;
    v.resize(n);
    for (int i = 0; i < m;i++) {
        cin >> a >> b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    for (int i = 0; i < n; i++) {
        if (!visited[i]) {
            visited[i] = 1;
            dfs(i, 1);
            visited[i] = 0;
        }
    }
    cout << 0;
}