func_code_string: #include <bits/stdc++.h>   using namespace std;   int memo[4][10000011];   int path;   int main() {     scanf( %d , &path);     memo[0][path] = 1;     for (int i = path - 1; i >= 0; i--) {       for (int j = 0; j < 4; ++j)         for (int k = 0; k < 4; ++k) {           if (j != k) {             memo[j][i] = (memo[j][i] + (memo[k][i + 1])) % 1000000007;           }         }     }     printf( %d n , memo[0][0]);     return 0;   }   