Submission #1128487

#	Time	Username	Problem	Language	Result	Execution time	Memory
1128487		Alihan_8	The Xana coup (BOI21_xanadu)	C++20	10 / 100	67 ms	6216 KiB

xanadu

#include <bits/stdc++.h>

using namespace std;

signed main(){
	int n; cin >> n;
	
	vector <vector<int>> adj(n);
	
	for ( int i = 1; i < n; i++ ){
		int u, v; cin >> u >> v;
		
		--u, --v;
		
		adj[u].push_back(v);
		adj[v].push_back(u);
	}
	
	vector <int> a(n);
	
	for ( auto &u: a ) cin >> u;
	
	int cnt = 0;
	
	for ( int i = 0; i + 1 < n; i++ ){
		if ( a[i] != 0 ){
			cnt += 1;
			
			a[i] ^= 1, a[i + 1] ^= 1;
			
			if ( i + 2 < n ) a[i + 2] ^= 1;
		}
	}
	
	if ( a[n - 1] != 0 ) return cout << "impossible\n", 0;
	
	cout << cnt << '\n';
}

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