Revise paste fb28b68942513

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

bool bit(int k, int n) {
    if (k == -1) return 1;
    return (n & (1 << k));
}

signed main() {
    ifstream cin("domino-covering-2.in");
    ofstream cout("domino-covering-2.out");
    int n, m;
    cin >> n >> m;
    vector <vector <bool> > a(n + 1, vector <bool> (m));
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            char c;
            cin >> c;
            a[i][j] = (c == '.') ? 0 : 1;
        }
    }
    vector <vector <int> > dp(m, vector <int> ((1 << m), 0ll));
    vector <int> dp_temp(1 << m);
    dp[0][(1 << m) - 1] = 1;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            int next_bit = (m + j + 1) % m;
            for (int k = 0; k < (1 << m); k++) {
                int bit_up = bit(j, k);
                int bit_left = bit(j - 1, k);
                int mask = k;
                int temp = dp[j][k];
                if (!a[i][j]) {
                    if (!bit_up) {
                        dp_temp[mask | (1 << j)] += temp;
                    } else {
                        if (!bit_left) {
                            dp_temp[mask | (1 << (j - 1))] += temp;
                            dp_temp[mask ^ (1 << j)] += temp;
                        } else {
                            dp_temp[mask ^ (1 << j)] += temp;
                        }
                    }
                } else {
                    if (bit_up) {
                        dp_temp[mask] += temp;
                    }
                }
            }
            for (int k = 0; k < (1 << m); k++) {
                dp[next_bit][k] = dp_temp[k];
                dp_temp[k] = 0;
            }
        }
    }
    cout << dp[0][(1 << m) - 1];
    return 0;
}