Submission #576340

#	Time	Username	Problem	Language	Result	Execution time	Memory
576340		talant117408	Newspapers (CEOI21_newspapers)	C++17	0 / 100	1 ms	312 KiB

newspapers

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef pair <int, int> pii;
typedef pair <ll, ll> pll;

#define long                unsigned long 
#define pb                  push_back
#define mp                  make_pair
#define all(v)              (v).begin(),(v).end()
#define rall(v)             (v).rbegin(),(v).rend()
#define lb                  lower_bound
#define ub                  upper_bound
#define sz(v)               int((v).size())
#define do_not_disturb      ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define endl                '\n'

void solve() {
    int n, m;
    cin >> n >> m;
    vector <vector <int>> graph(n+1);
    vector <int> used(n+1);
    for (int i = 1; i <= m; i++) {
        int a, b;
        cin >> a >> b;
        graph[a].pb(b);
        graph[b].pb(a);
    }
    int has_cycle = 0;
    function<void(int, int)> dfs = [&](int v, int p) {
        used[v] = 1;
        for (auto to : graph[v]) {
            if (used[to]) {
                if (used[to] == 1 && to != p) {
                    has_cycle = 1;
                }
                continue;
            }
            dfs(to, v);
        }
        used[v] = 2;
    };
    dfs(1, 1);
    if (has_cycle) cout << "NO" << endl;
    else cout << "YES" << endl;
}

int main() {
    do_not_disturb
    
    int t = 1;
    //~ cin >> t;
    while (t--) {
        solve();
    }
    
    return 0;
}

• Subtask 1: 0 / 12
• Subtask 2: 0 / 8
• Subtask 3: 0 / 80