Example of O(n!)?

Question

What is an example (in code) of a O(n!) function? It should take appropriate number of operations to run in reference to n; that is, I\'m asking a

Answer 1

Finding the determinant with expansion by minors.

Very good explanation here.

# include 
# include 

bool det_by_minor()
{   bool ok = true;

    // dimension of the matrix
    size_t n = 3;

    // construct the determinat object
    CppAD::det_by_minor Det(n);

    double  a[] = {
        1., 2., 3.,  // a[0] a[1] a[2]
        3., 2., 1.,  // a[3] a[4] a[5]
        2., 1., 2.   // a[6] a[7] a[8]
    };
    CPPAD_TEST_VECTOR A(9);
    size_t i;
    for(i = 0; i < 9; i++)
        A[i] = a[i];


    // evaluate the determinant
    double det = Det(A);

    double check;
    check = a[0]*(a[4]*a[8] - a[5]*a[7])
          - a[1]*(a[3]*a[8] - a[5]*a[6])
          + a[2]*(a[3]*a[7] - a[4]*a[6]);

    ok = det == check;

    return ok;
}

Code from here. You will also find the necessary .hpp files there.