Given a set of numbers, find the Length of the Longest Geometrix Progression (LLGP) in it. The common ratio of GP must be an integer.
set[] = {5, 7, 10, 15, 20, 29}
output = 3
The longest arithmetic progression is {5, 10, 20}
set[] = {3, 9, 27, 81}
output = 4