oj.uz

Submission #871414

# Submission time Handle Problem Language Result Execution time Memory
871414 2023-11-10T19:11:04 Z Cyber_Wolf The Xana coup (BOI21_xanadu) C++17
0 / 100
 1000 ms 14168 KB 
#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][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(valid)	cout << i << '\n';
	}
	// if(ans > n)
	// {
		// cout << "impossible\n";
		// return 0;
	// }
	// cout << ans << '\n';
	// return 0;
	// for(int i = 1; i <= n; i++)
	// {
		// memset(dp, -1, sizeof(dp));
		// ans = min(ans, dfs(i, 0, -1));
	// }
	memset(dp, 0x3f, sizeof(dp));
	dp[0][0][0] = dp[0][1][0] = 0;
	for(int i = 1; i <= n; i++)
	{
		for(int j = 0; j < 2; j++)
		{
			for(int k = 0; k < 2; k++)
			{
				dp[i][j][k] = min(dp[i][j][k], dp[i-1][k][col[i]^j^k]+k);
				if(dp[i][j][k] > n)	dp[i][j][k] = n+1;
				// cout << dp[i][j][k] << ' ';
			}
		}
		// cout << '\n';
	}
	if(min(dp[n][0][1], dp[n][0][0]) > n)
	{
		cout << "impossible\n";
		return 0;
	}
	cout << min(dp[n][0][0], dp[n][0][1]) << '\n';
}

Subtask #1
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 13 ms 14168 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #2
0 / 15.0

# Verdict Execution time Memory Grader output
1 Incorrect 13 ms 14168 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #3
0 / 10.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1054 ms 13256 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #4
0 / 40.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1012 ms 13392 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #5
0 / 30.0

# Verdict Execution time Memory Grader output
1 Incorrect 13 ms 14168 KB Output isn't correct
2 Halted 0 ms 0 KB -