func_code_string: #include <bits/stdc++.h>   using namespace std;   int mod = 1e9 + 7;   int f[105][105][105], len[105], n, m;   char s[105];   int qpow(int x, int y) {     int res = 1;     while (y) {       if (y % 2) res = 1ll * res * x % mod;       x = 1ll * x * x % mod;       y /= 2;     }     return res;   }   int dfs(int x, int l, int r) {     if (f[x][l][r] != -1) return f[x][l][r];     if (x <= 1) return (l == r) && (s[l] == (x +  0 ));     int cnt = 0;     cnt = (cnt +            1ll * dfs(x - 1, l, r) * ((r == n) ? qpow(2, len[x - 2]) : 1) % mod) %           mod;     cnt = (cnt +            1ll * dfs(x - 2, l, r) * ((l == 1) ? qpow(2, len[x - 1]) : 1) % mod) %           mod;     for (int k = l; k < r; k++)       cnt = (cnt + 1ll * dfs(x - 1, l, k) * dfs(x - 2, k + 1, r) % mod) % mod;     return f[x][l][r] = cnt;   }   int main() {     ios_base::sync_with_stdio(false);     cin >> n >> m;     memset(f, -1, sizeof(f));     len[1] = 1;     len[0] = 1;     for (int i = 2; i <= m; i++) len[i] = (len[i - 1] + len[i - 2]) % (mod - 1);     cin >> s + 1;     printf( %d n , dfs(m, 1, n));   }   