View Compilation Error

0_0_25991495_990.cpp:6:9: error: array bound is not an integer constant before ']' token
 ll fac[N];
         ^
0_0_25991495_990.cpp: In function 'void init()':
0_0_25991495_990.cpp:8:5: error: 'fac' was not declared in this scope
     fac[0]=1;
     ^
0_0_25991495_990.cpp: In function 'll dfs(ll, ll, ll)':
0_0_25991495_990.cpp:14:39: error: 'fac' was not declared in this scope
     if(x==n||y==m) return dp[x][y][z]=fac[n*m-z];
                                       ^