#include<iostream>
#include<algorithm>
#include<vector>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
#define ff first
#define ss second
const int N = 20, M = 400;
int n, m;
pii edge[N];
vector<int> g[N];
void loadGraph(int mask) {
for (int i = 1; i <= n; ++i) g[i].clear();
for (int i = 0; i < m; ++i)
if (mask >> i & 1)
g[edge[i].ss].push_back(edge[i].ff);
else g[edge[i].ff].push_back(edge[i].ss);
}
int vis[N];
bool dfs(int u, int tme) {
vis[u] = tme;
for (int v : g[u]) {
if (!vis[v]) dfs(v, tme);
else if (vis[v] == tme) return true;
}
return false;
}
bool check() {
fill(vis + 1, vis + n + 1, 0);
for (int i = 1; i <= n; ++i)
if (!vis[i] && dfs(i, i)) return false;
return true;
}
int lg[N];
int main() {
cin.tie(NULL)->sync_with_stdio(false);
cin >> n >> m;
for (int i = 0; i < m; ++i)
cin >> edge[i].ff >> edge[i].ss;
int cnt(0);
for (int mask = 0; mask < (1 << m); ++mask) {
lg[mask] = lg[mask >> 1] + (mask & 1);
loadGraph(mask);
if (check()) cnt += lg[mask];
}
cout << cnt << '\n';
}
/** /\_/\
* (= ._.)
* / >0 \>1
**/
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
1 ms |
256 KB |
Output is correct |
3 |
Correct |
0 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
204 KB |
Output is correct |
5 |
Correct |
1 ms |
204 KB |
Output is correct |
6 |
Incorrect |
0 ms |
204 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
1 ms |
256 KB |
Output is correct |
3 |
Correct |
0 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
204 KB |
Output is correct |
5 |
Correct |
1 ms |
204 KB |
Output is correct |
6 |
Incorrect |
0 ms |
204 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
1 ms |
256 KB |
Output is correct |
3 |
Correct |
0 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
204 KB |
Output is correct |
5 |
Correct |
1 ms |
204 KB |
Output is correct |
6 |
Incorrect |
0 ms |
204 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
1 ms |
256 KB |
Output is correct |
3 |
Correct |
0 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
204 KB |
Output is correct |
5 |
Correct |
1 ms |
204 KB |
Output is correct |
6 |
Incorrect |
0 ms |
204 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
1 ms |
256 KB |
Output is correct |
3 |
Correct |
0 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
204 KB |
Output is correct |
5 |
Correct |
1 ms |
204 KB |
Output is correct |
6 |
Incorrect |
0 ms |
204 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |