func_code_string: #include <bits/stdc++.h>   const int MAXN = 60;   int n, P, A[MAXN];   const int mod = 1000000007;   void reduce(int& x) { x += x >> 31 & mod; }   int mul(int a, int b) { return (long long)a * b % mod; }   int pow(int a, int b, int res = 1) {     for (; b; b >>= 1, a = mul(a, a))       if (b & 1) res = mul(res, a);     return res;   }   int dp[MAXN][MAXN][MAXN];   int main() {     std::ios_base::sync_with_stdio(false), std::cin.tie(0);     std::cin >> n >> P;     for (int i = 1; i <= n; ++i) std::cin >> A[i];     dp[0][0][0] = 1;     for (int i = 1; i <= n; ++i)       for (int j = 0; j <= i; ++j)         for (int k = 0; k <= i; ++k)           if (dp[i - 1][j][k]) {             if (A[i] == 0 || A[i] == -1) {               int t = pow(2, i - 1 - (!!k), dp[i - 1][j][k]);               reduce(dp[i][j + 1][k] += t - mod);               if (k) reduce(dp[i][j][k] += t - mod);             }             if (A[i] == 1 || A[i] == -1) {               int t = pow(2, i - 1 - (!!j), dp[i - 1][j][k]);               reduce(dp[i][j][k + 1] += t - mod);               if (j) reduce(dp[i][j][k] += t - mod);             }           }     int ans = 0;     for (int i = 0; i <= n; ++i)       for (int j = 0; j <= n; ++j)         if ((i + j & 1) == P) reduce(ans += dp[n][i][j] - mod);     std::cout << ans << std::endl;     return 0;   }   