Submission #1128580

#	Time	Username	Problem	Language	Result	Execution time	Memory
1128580		Alihan_8	Snake Escaping (JOI18_snake_escaping)	C++20	100 / 100	1090 ms	49612 KiB

snake_escaping

#include <bits/stdc++.h>

using namespace std;

signed main(){
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
	
	int n, q; cin >> n >> q;
	
	string s; cin >> s;
	
	for ( auto &v: s ) v -= '0';
	
	vector <int> pw(n + 1, 1);
	
	for ( int i = 1; i <= n; i++ ){
		pw[i] = pw[i - 1] * 3;
	}
	
	int B = min(n, 7), m = n - B;
	
	vector <int> val(q), lst(q);
	
	for ( int i = 0; i < q; i++ ){
		string t; cin >> t;
		
		for ( int j = 0; j < m; j++ ){
			val[i] = val[i] + pw[j] * (t[j] == '?' ? 2 : t[j] - '0');
		}
		
		for ( int j = n - 1; j >= m; j-- ){
			lst[i] = lst[i] * 3 + (t[j] == '?' ? 2 : t[j] - '0');
		}
	}
	
	vector <int> f(pw[m]), pt(pw[m], -1);
	
	for ( int mask = 0; mask < pw[m]; mask++ ){
		for ( int i = 0; i < m; i++ ){
			f[mask] = f[mask] * 2 + mask / pw[i] % 3;
			
			if ( mask / pw[i] % 3 == 2 ) pt[mask] = i;
		}
	}
	
	vector <int> ans(q);
	
	for ( int lf = 0; lf < (1 << B); lf++ ){
		vector <int> is(pw[B]);
		
		for ( int mask = 0; mask < (1 << B); mask++ ){
			int cnt = 0;
			
			for ( int i = 0; i < n; i++ ){
				int b = lf >> i & 1;
				
				if ( mask >> i & 1 ) cnt = cnt + pw[i] * 2;
				else cnt = cnt + pw[i] * b;
			}
			
			is[cnt] = 1;
		}
		
		int cur = 0;
		
		for ( int i = 0; i < B; i++ ) cur = cur * 2 + (lf >> i & 1);
		
		vector <int> dp(pw[m]);
		
		for ( int mask = 0; mask < pw[m]; mask++ ){
			if ( pt[mask] != -1 ){	
				dp[mask] = dp[mask - pw[pt[mask]]] + dp[mask - pw[pt[mask]] * 2];
			} else dp[mask] = s[(f[mask] << B) + cur];
		}
		
		for ( int i = 0; i < q; i++ ){
			ans[i] += dp[val[i]] * is[lst[i]];
		}
	}
	
	for ( auto &x: ans ) cout << x << '\n';
}

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 10 / 10
• Subtask 4: 53 / 53
• Subtask 5: 25 / 25