#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int N = 18;
const int mod = 998244353;
ll ways[1<<N][N];
ll ways2[1<<N];
int undirected_edge[N];
int main(){
int n,m,a,b;
cin >> n >> m;
for(int i = 1; i <= m; i++){
cin >> a >> b;
a--;b--;
undirected_edge[a] ^= (1<<b);
undirected_edge[b] ^= (1<<a);
}
for(int i = 0; i < n; i++){
ways[1<<i][i] = 1;
ways2[1<<i] = 1;
}
for(int i = 0; i < (1<<n); i++){
if(! (i&(i-1))) continue;
for(int j = 0; j < n; j++){
if(! (i&(1<<j))) continue;
ways[i][j] = ways2[i^(1<<j)];
for(int k = 0; k < n; k++){
if((! (i&(1<<j))) || (k == j)) continue;
if((! (undirected_edge[j]&(1<<k))) && (k < j)){
ways[i][j] -= ways[i^(1<<k)][j];
if(ways[i][j] < 0) ways[i][j] += mod;
}
}
ways[i][j] %= mod;
ways2[i] += ways[i][j];
}
ways2[i] %= mod;
}
ll ans = ways2[(1<<n)-1];
if(ans&1) ans += mod;
ans >>= 1;
ans *= m; ans %= mod;
cout << ans;
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
308 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Incorrect |
0 ms |
308 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
308 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Incorrect |
0 ms |
308 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
308 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Incorrect |
0 ms |
308 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
308 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Incorrect |
0 ms |
308 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
308 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Incorrect |
0 ms |
308 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |