#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;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
1 ms |
312 KB |
Unexpected end of file - int32 expected |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
1 ms |
212 KB |
Unexpected end of file - int32 expected |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
1 ms |
312 KB |
Unexpected end of file - int32 expected |
2 |
Halted |
0 ms |
0 KB |
- |