Submission #110121

#	Time	Username	Problem	Language	Result	Execution time	Memory
110121		popovicirobert	Snake Escaping (JOI18_snake_escaping)	C++14	75 / 100	2063 ms	21504 KiB

snake_escaping

#include <bits/stdc++.h>
#define lsb(x) (x & (-x))
#define ll long long
#define ull unsigned long long
// 217
// 44

using namespace std;

int dp[2][1 << 20];
char str[1 << 20];
vector <int> bit;

void bktQ(int p, int cnf, int &ans) {
    if(p == bit.size()) {
        ans += str[cnf] - '0';
    }
    else {
        bktQ(p + 1, cnf, ans);
        bktQ(p + 1, cnf + (1 << bit[p]), ans);
    }
}

void bkt(int p, int cnf, int &ans, int cnt, bool t) {
    if(p == bit.size()) {
        if(cnt & 1) {
            ans -= dp[t][cnf];
        }
        else {
            ans += dp[t][cnf];
        }
    }
    else {
        bkt(p + 1, cnf, ans, cnt, t);
        bkt(p + 1, cnf ^ (1 << bit[p]), ans, cnt + 1, t);
    }

}

int main() {
    //ifstream cin("A.in");
    //ofstream cout("A.out");
    int i, l, q;
    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);

    cin >> l >> q >> str;

    for(int conf = 0; conf < (1 << l); conf++) {
        dp[0][conf ^ ((1 << l) - 1)] = str[conf] - '0';
        dp[1][conf] = str[conf] - '0';
    }

    for(i = 0; i < 2; i++) {
        for(int bit = 0; bit < l; bit++) {
            for(int conf = 0; conf < (1 << l); conf++) {
                if(conf & (1 << bit)) {
                    dp[i][conf] += dp[i][conf ^ (1 << bit)];
                }
            }
        }
    }

    while(q > 0) {
        q--;

        string cur;
        cin >> cur;
        reverse(cur.begin(), cur.end());

        int numq = 0, num0 = 0, num1 = 0;
        int val = 0;
        for(i = 0; i < l; i++) {
            if(cur[i] == '0') {
                num0++;
            }
            if(cur[i] == '1') {
                num1++;
            }
            if(cur[i] == '?') {
                numq++;
            }
        }

        int mn = min(numq, min(num0, num1));
        bit.clear();
        int ans = 0, cnf = 0;

        if(numq == mn) {

            for(i = 0; i < l; i++) {
                if(cur[i] == '?') {
                    bit.push_back(i);
                }
                else {
                    cnf += (1 << i) * (cur[i] == '1');
                }
            }

            bktQ(0, cnf, ans);
        }
        else if(num0 == mn) {

            for(i = 0; i < l; i++) {
                if(cur[i] == '0') {
                    bit.push_back(i);
                }
                if(cur[i] != '1') {
                    cnf += (1 << i);
                }
            }

            bkt(0, cnf, ans, 0, 0);
        }
        else if(num1 == mn) {

             for(i = 0; i < l; i++) {
                if(cur[i] == '1') {
                    bit.push_back(i);
                }
                if(cur[i] != '0') {
                    cnf += (1 << i);
                }
            }

            bkt(0, cnf, ans, 0, 1);
        }

        cout << ans << "\n";

    }

    //cin.close();
    //cout.close();
    return 0;
}

Compilation message (stderr)

snake_escaping.cpp: In function 'void bktQ(int, int, int&)':
snake_escaping.cpp:15:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if(p == bit.size()) {
        ~~^~~~~~~~~~~~~
snake_escaping.cpp: In function 'void bkt(int, int, int&, int, bool)':
snake_escaping.cpp:25:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if(p == bit.size()) {
        ~~^~~~~~~~~~~~~
snake_escaping.cpp: In function 'int main()':
snake_escaping.cpp:72:13: warning: unused variable 'val' [-Wunused-variable]
         int val = 0;
             ^~~

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 10 / 10
• Subtask 4: 53 / 53
• Subtask 5: 0 / 25