Submission #1125080

#	Time	Username	Problem	Language	Result	Execution time	Memory
1125080		Pannda	Nautilus (BOI19_nautilus)	C++20	100 / 100	130 ms	560 KiB

nautilus

#include <bits/stdc++.h>
using namespace std;

const int N = 501;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, m, k;
    cin >> n >> m >> k;
    vector<bitset<N>> mask(n);
    for (int i = 0; i < n; i++) {
        string s;
        cin >> s;
        for (int j = 0; j < m; j++) {
            if (s[j] == '.') mask[i].set(j);
        }
    }
    string s;
    cin >> s;

    vector<bitset<N>> prev = mask;
    vector<bitset<N>> dp(n);
    bitset<N> none;

    for (char ch : s) {
        if (ch == 'W') {
            for (int i = 0; i < n; i++) {
                dp[i] = (prev[i] >> 1) & mask[i];
            }
        }
        if (ch == 'E') {
            for (int i = 0; i < n; i++) {
                dp[i] = (prev[i] << 1) & mask[i];
            }
        }
        if (ch == 'N') {
            for (int i = 0; i + 1 < n; i++) {
                dp[i] = prev[i + 1] & mask[i];
            }
            dp[n - 1].reset();
        }
        if (ch == 'S') {
            dp[0].reset();
            for (int i = 1; i < n; i++) {
                dp[i] = prev[i - 1] & mask[i];
            }
        }
        if (ch == '?') {
            for (int i = 0; i < n; i++) {
                dp[i] = ( (prev[i] >> 1) | (prev[i] << 1) | (i == 0 ? none : prev[i - 1]) | (i == n - 1 ? none : prev[i + 1]) ) & mask[i];
            }
        }
        prev = dp;

    }

    int ans = 0;
    for (int i = 0; i < n; i++) {
        ans += prev[i].count();
    }
    cout << ans << '\n';

}

• Subtask 1: 29 / 29
• Subtask 2: 37 / 37
• Subtask 3: 34 / 34