#include <bits/stdc++.h>
using namespace std;
#define lg long long
#define fastio ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
const lg N = 2e5+5;
vector<lg> adj[N];
lg dp[N][2], col[N];
// lg solve(lg src, lg b, lg par)
// {
// auto&ret = dp[src][b];
// if(~ret) return ret;
// ret = 1e18;
// for(int i = 0; i < (1ll << adj[src].size()); i++)
// {
// lg x = (b^(__builtin_popcount(i)&1));
// for(int j = 0; j < adj[src].size(); j++)
// {
//
// }
// }
// return ret;
// }
//par true -> must
//par false -> must not
lg newcol[N];
int main()
{
lg n;
cin >> n;
for(int i = 1; i < n; i++)
{
lg u, v;
cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
}
for(int i = 1; i <= n; i++)
{
cin >> col[i];
}
lg ans = 1e18;
for(int i = 0; i < (1ll << n); i++)
{
for(int j = 0; j < n; j++)
{
newcol[j+1] ^= col[j+1];
if((1ll << j)&i)
{
for(auto it : adj[j+1])
{
newcol[it] ^= 1;
}
newcol[j+1] ^= 1;
}
}
lg valid = 1;
for(int j = 1; j <= n; j++)
{
valid &= (newcol[j] == 0);
newcol[j] = 0;
}
lg x = __builtin_popcount(i);
if(valid) ans = min(ans, x);
}
if(ans > n)
{
cout << "impossible\n";
return 0;
}
cout << ans << '\n';
// for(int i = 1; i <= n; i++)
// {
// memset(dp, -1, sizeof(dp));
// ans = min(ans, dfs(i, 0, -1));
// }
// dp[0][1] = 1e18;
for(int i = 1; i <= n; i++)
{
if(!col[i])
{
dp[i][0] = dp[i-1][0];
dp[i][1] = dp[i-1][1]+1;
}
else{
dp[i][0] = dp[i-1][1]+1;
dp[i][1] = dp[i-1][0];
}
}
// if(dp[n][0] > n)
// {
// cout << "impossible\n";
// return 0;
// }
// cout << dp[n][0] << '\n';
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
13 ms |
9048 KB |
Output is correct |
2 |
Correct |
3 ms |
9052 KB |
Output is correct |
3 |
Correct |
107 ms |
9144 KB |
Output is correct |
4 |
Correct |
107 ms |
9048 KB |
Output is correct |
5 |
Correct |
109 ms |
9140 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
13 ms |
9048 KB |
Output is correct |
2 |
Correct |
3 ms |
9052 KB |
Output is correct |
3 |
Correct |
107 ms |
9144 KB |
Output is correct |
4 |
Correct |
107 ms |
9048 KB |
Output is correct |
5 |
Correct |
109 ms |
9140 KB |
Output is correct |
6 |
Correct |
14 ms |
9052 KB |
Output is correct |
7 |
Correct |
3 ms |
9052 KB |
Output is correct |
8 |
Correct |
111 ms |
9140 KB |
Output is correct |
9 |
Correct |
108 ms |
9396 KB |
Output is correct |
10 |
Correct |
111 ms |
9144 KB |
Output is correct |
11 |
Execution timed out |
1062 ms |
9052 KB |
Time limit exceeded |
12 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Execution timed out |
1064 ms |
14672 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Execution timed out |
1018 ms |
14552 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
13 ms |
9048 KB |
Output is correct |
2 |
Correct |
3 ms |
9052 KB |
Output is correct |
3 |
Correct |
107 ms |
9144 KB |
Output is correct |
4 |
Correct |
107 ms |
9048 KB |
Output is correct |
5 |
Correct |
109 ms |
9140 KB |
Output is correct |
6 |
Correct |
14 ms |
9052 KB |
Output is correct |
7 |
Correct |
3 ms |
9052 KB |
Output is correct |
8 |
Correct |
111 ms |
9140 KB |
Output is correct |
9 |
Correct |
108 ms |
9396 KB |
Output is correct |
10 |
Correct |
111 ms |
9144 KB |
Output is correct |
11 |
Execution timed out |
1062 ms |
9052 KB |
Time limit exceeded |
12 |
Halted |
0 ms |
0 KB |
- |