sorting int array with only 3 elements

Question

I have this array:

int [] myarray =  {17, 6, 8};

What is the optimal way to sort this array, in pseudocode?

Thanks!

Answer 1

This code makes 2 or 3 comparisons and 4 memory records in the worst case, as opposed to another answer (always 3 comparisons and 9 memory records in the worst case).

if a[0] < a[1]:
    if a[1] > a[2]:
        if a[0] < a[2]:
            temp = a[1]
            a[1] = a[2]
            a[2] = temp
        else:
            temp = a[0]
            a[0] = a[2]
            a[2] = a[1]
            a[1] = temp
    else:
        # do nothing
else:
    if a[1] < a[2]:
        if a[0] < a[2]:
            temp = a[0]
            a[0] = a[1]
            a[1] = temp
        else:
            temp = a[0]
            a[0] = a[1]
            a[1] = a[2]
            a[2] = temp
    else:
        temp = a[0]
        a[0] = a[2]
        a[2] = temp