View Compilation Error

0_0_33905258_7509.cpp: In function 'void solve()':
0_0_33905258_7509.cpp:21:17: error: 'f' was not declared in this scope
                 f[i][j][k]=0;
                 ^
0_0_33905258_7509.cpp:22:5: error: 'f' was not declared in this scope
     f[1][0][0]=1;
     ^