Submission #775527

#	Time	Username	Problem	Language	Result	Execution time	Memory
775527		1bin	Snake Escaping (JOI18_snake_escaping)	C++14	100 / 100	1410 ms	43348 KiB

snake_escaping

#include <bits/stdc++.h>
 
using namespace std;
 
#define all(v) v.begin(), v.end()
typedef long long ll;
int n, q, a[1 << 20], S[1 << 20], T[1 << 20], cnt[2], ans, p;
string s;
 
void f(int i, int op, int st){
    if(i == n){
        if(!op) ans += a[st];
        else if(op == 1){
            if(p & 1) ans -= S[st];
            else ans += S[st];
        }
        else{
            if(p & 1) ans -= T[st];
            else ans += T[st];
            //cout << i << ' ' << st << ' ' << T[st] << ' ' << ans << '\n';
        }
        return;
    }
    if(!op){
        if(s[i] == '?') {
            f(i + 1, op, st);
            f(i + 1, op, st | 1 << i);
        }
        else {
            if(s[i] == '1') st |= 1 << i;
            f(i + 1, op, st);
        }
    }
    else if(op == 1){
        if(s[i] == '1'){
            f(i + 1, op, st | 1 << i);
            p++;
            f(i + 1, op, st);
            p--;
        }
        else{
            if(s[i] == '?') st |= 1 << i;
            f(i + 1, op, st);
        }
    }
    else{
        if(s[i] == '0'){
            f(i + 1, op, st);
            p++;
            f(i + 1, op, st | 1 << i);
            p--;
        }
        else{
            if(s[i] == '1') st |= 1 << i;
            f(i + 1, op, st);
        }
    }
    return;
}
 
int main(void){
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    
    cin >> n >> q >> s;
    for(int i = 0; i < 1 << n; i++) {
        a[i] = s[i] - '0';
        S[i] = T[i] = a[i];
    }
    for(int i = 0; i < n; i++)
        for(int mask = 0; mask < 1 << n; mask++) {
            if(mask & (1 << i)) S[mask] += S[mask ^ (1 << i)];
            if(!(mask & (1 << i))) T[mask] += T[mask ^ (1 << i)];
        }
    while(q--){
        cin >> s;
        reverse(all(s));
        cnt[0] = cnt[1] = 0;
        for(int i = 0; i < n; i++){
            if(s[i] == '?') cnt[0]++;
            else if(s[i] == '1') cnt[1]++;
        }
        ans = 0;
        if(cnt[0] <= n / 3) f(0, 0, 0);
        else if(cnt[1] <= n / 3) f(0, 1, 0);
        else f(0, 2, 0);
        cout << ans << '\n';
    }
    
    return 0;
}

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