#include<bits/stdc++.h>
#define MASK(x) (1LL << (x))
#define BIT(x, i) (((x) >> (i)) & 1)
using namespace std;
const int MAXN = 18;
const int MOD = 998244353;
int N, M;
int adj[MAXN];
vector<pair<int, int>> e;
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cin >> N >> M;
for(int i = 0; i < M; i++) {
int a, b;
cin >> a >> b;
a--;
b--;
adj[a] ^= MASK(b);
e.push_back(make_pair(a, b));
}
//if(M <= 20)
{
int ans = 0;
for(int mask = 0; mask < MASK(M); mask++) {
vector<int> new_adj(N, 0);
for(int i = 0; i < M; i++) {
if(BIT(mask, i))
new_adj[e[i].second] ^= MASK(e[i].first);
else
new_adj[e[i].first] ^= MASK(e[i].second);
}
vector<int> vis(N, 0);
vector<int> root;
for(int i = 0; i < N; i++) {
for(int j = 0; j < N; j++) {
if(BIT(new_adj[i], j)) {
vis[j] = 1;
}
}
}
for(int i = 0; i < N; i++) {
if(vis[i] == 0) {
root.push_back(i);
}
else {
vis[i] = 0;
}
}
function<void(int)> dfs;
bool good = !root.empty();
dfs = [&](int u) {
if(!good)
return;
vis[u] = 1;
for(int i = 0; i < N; i++) {
if(BIT(new_adj[u], i) && vis[i] == 1) {
good = false;
return;
}
}
for(int i = 0; i < N; i++) {
if(BIT(new_adj[u], i)) {
dfs(i);
if(!good)
return;
}
}
vis[u] = 2;
};
for(int i : root)
dfs(i);
if(good && root.size())
(ans += __builtin_popcount(mask)) %= MOD;
}
cout << ans;
}
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
212 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Correct |
1 ms |
212 KB |
Output is correct |
4 |
Correct |
1 ms |
212 KB |
Output is correct |
5 |
Correct |
1 ms |
212 KB |
Output is correct |
6 |
Correct |
1 ms |
212 KB |
Output is correct |
7 |
Correct |
1 ms |
212 KB |
Output is correct |
8 |
Correct |
0 ms |
212 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
212 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Correct |
1 ms |
212 KB |
Output is correct |
4 |
Correct |
1 ms |
212 KB |
Output is correct |
5 |
Correct |
1 ms |
212 KB |
Output is correct |
6 |
Correct |
1 ms |
212 KB |
Output is correct |
7 |
Correct |
1 ms |
212 KB |
Output is correct |
8 |
Correct |
0 ms |
212 KB |
Output is correct |
9 |
Correct |
1 ms |
212 KB |
Output is correct |
10 |
Correct |
1 ms |
324 KB |
Output is correct |
11 |
Incorrect |
1 ms |
212 KB |
Output isn't correct |
12 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
212 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Correct |
1 ms |
212 KB |
Output is correct |
4 |
Correct |
1 ms |
212 KB |
Output is correct |
5 |
Correct |
1 ms |
212 KB |
Output is correct |
6 |
Correct |
1 ms |
212 KB |
Output is correct |
7 |
Correct |
1 ms |
212 KB |
Output is correct |
8 |
Correct |
0 ms |
212 KB |
Output is correct |
9 |
Correct |
1 ms |
212 KB |
Output is correct |
10 |
Correct |
1 ms |
324 KB |
Output is correct |
11 |
Incorrect |
1 ms |
212 KB |
Output isn't correct |
12 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
212 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Correct |
1 ms |
212 KB |
Output is correct |
4 |
Correct |
1 ms |
212 KB |
Output is correct |
5 |
Correct |
1 ms |
212 KB |
Output is correct |
6 |
Correct |
1 ms |
212 KB |
Output is correct |
7 |
Correct |
1 ms |
212 KB |
Output is correct |
8 |
Correct |
0 ms |
212 KB |
Output is correct |
9 |
Correct |
1 ms |
212 KB |
Output is correct |
10 |
Correct |
1 ms |
324 KB |
Output is correct |
11 |
Incorrect |
1 ms |
212 KB |
Output isn't correct |
12 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
212 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Correct |
1 ms |
212 KB |
Output is correct |
4 |
Correct |
1 ms |
212 KB |
Output is correct |
5 |
Correct |
1 ms |
212 KB |
Output is correct |
6 |
Correct |
1 ms |
212 KB |
Output is correct |
7 |
Correct |
1 ms |
212 KB |
Output is correct |
8 |
Correct |
0 ms |
212 KB |
Output is correct |
9 |
Correct |
1 ms |
212 KB |
Output is correct |
10 |
Correct |
1 ms |
324 KB |
Output is correct |
11 |
Incorrect |
1 ms |
212 KB |
Output isn't correct |
12 |
Halted |
0 ms |
0 KB |
- |