Submission #986204

#	Time	Username	Problem	Language	Result	Execution time	Memory
986204		batsukh2006	The Xana coup (BOI21_xanadu)	C++17	5 / 100	1049 ms	8788 KiB

xanadu

#include<iostream>
#include<stdio.h>
#include<math.h>
#include<map>
#include<string>
#include<algorithm>
#include<vector>
#include<string.h>
#include<utility>
#include<set>
#include<cmath>
#include<queue>
#include<deque>
#include<functional>
#include<stack>
#include<limits.h>
#include<iomanip>
#include<unordered_map> 
#include<numeric>
#include<tuple>
using namespace std;
 
#define MOD 1000000007
#define int long long
#define ff first
#define ss second
#define endl '\n'
void solve(){
	int n; cin>>n;
	vector<int> v[n],c(n);
	for(int i=1; i<n; i++){
		int a,b; cin>>a>>b,a--,b--;
		v[a].push_back(b);
		v[b].push_back(a);
	}
	int ans=1e9;
	for(int i=0; i<n; i++) cin>>c[i];
	for(int i=0; i<(1<<n); i++){
		vector<int> tmp=c;
		for(int j=0; j<n; j++){
			if(i&(1<<j)){
				tmp[j]^=1;
				for(auto node: v[j]){
					tmp[node]^=1;
				}
			}
		}
		int ok=1;
		for(int j=0; j<n; j++){
			if(tmp[j]) ok=0;
		}
		int move=__builtin_popcount(i);
		if(ok) ans=min(ans,move);
	}
	if(ans==1e9) cout<<"impossible";
	else cout<<ans;
}
signed main(){
    // freopen("248.in", "r", stdin);
    // freopen("248.out", "w", stdout);
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    
    int t=1;
//    cin>>t;	
    while(t--){
        solve();
        cout<<endl;
    }
    return 0;
}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

• Subtask 1: 5 / 5
• Subtask 2: 0 / 15
• Subtask 3: 0 / 10
• Subtask 4: 0 / 40
• Subtask 5: 0 / 30