View Compilation Error

0_0_33694034_30271.cpp: In function 'll det(int, ll (*)[309])':
0_0_33694034_30271.cpp:15:35: error: 'qpow' was not declared in this scope
    ll t=a[i][i]*qpow(a[j][i],mod-2)%mod;
                                   ^
0_0_33694034_30271.cpp: In function 'int solve()':
0_0_33694034_30271.cpp:39:17: error: too few arguments to function 'll det(int, ll (*)[309])'
  int res=det(n-1);
                 ^
0_0_33694034_30271.cpp:9:4: note: declared here
 ll det(int n,ll a[maxn][maxn]){
    ^