#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 1e5 + 10, MOD = 998244353;
bool is[N];
vector<int> g[N];
int check(int n){
int res = 1e9;
for(int i = 0;i < (1 << n);i++){
for(int j = 0;j < n;j++){
if((i >> j) & 1){
is[j + 1] = 1;
}else{
is[j + 1] = 0;
}
}
bool ok = true;
for(int j = 1;j <= n;j++){
int x = 0;
for(int to:g[j]){
x += is[to];
}
if(x != 1){
ok = false;
break;
}
}
if(ok){
res = min(res,__builtin_popcount(i));
}
}
if(res == 1e9) res = -1;
return res;
}
int n;
void solve(){
for(int i = 1;i <= n;i++){
int x,y;
cin >> x >> y;
g[x].push_back(y);
g[y].push_back(x);
}
int res = check(n);
if(res == -1){
cout << res;
return;
}
assert(res == n / 2 || res == (n + 1) / 2 || res == n / 2 - 1);
cout << res;
}
void test(){
cin >> n;
if(n <= 20){
solve();
return;
}
if(n % 4){
cout << -1;
return;
}
cout << n / 2;
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
int T = 1;
// cin >> T;
for(int i = 1;i <= T;i++)
{
test();
}
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
2648 KB |
Output is correct |
2 |
Correct |
1 ms |
2648 KB |
Output is correct |
3 |
Correct |
1 ms |
2652 KB |
Output is correct |
4 |
Correct |
1 ms |
2652 KB |
Output is correct |
5 |
Correct |
1 ms |
2652 KB |
Output is correct |
6 |
Correct |
1 ms |
2648 KB |
Output is correct |
7 |
Correct |
1 ms |
2652 KB |
Output is correct |
8 |
Correct |
1 ms |
2568 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
17 ms |
5212 KB |
Execution killed with signal 6 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
17 ms |
5212 KB |
Execution killed with signal 6 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
2648 KB |
Output is correct |
2 |
Correct |
1 ms |
2648 KB |
Output is correct |
3 |
Correct |
1 ms |
2652 KB |
Output is correct |
4 |
Correct |
1 ms |
2652 KB |
Output is correct |
5 |
Correct |
1 ms |
2652 KB |
Output is correct |
6 |
Correct |
1 ms |
2648 KB |
Output is correct |
7 |
Correct |
1 ms |
2652 KB |
Output is correct |
8 |
Correct |
1 ms |
2568 KB |
Output is correct |
9 |
Runtime error |
17 ms |
5212 KB |
Execution killed with signal 6 |
10 |
Halted |
0 ms |
0 KB |
- |