Question

I have an array which can have N nested array where N can contain M arrays where both N and M are >= 1. Some examples include the following:

[[[1,2,3],[3,4,5]],[[2,1,1]]]

or

[[[1,2,3]],[]]]

and finally

[[[1,2,3],[3,4,5]],[[2,1,1]], [[1,1,1],[2,2,2]]]

I need something that returns a boolean true or false if there is a duplicate value for the 0^th element in a nested array, the issue is the composite array is not the unique identifier. Only the 0^th element in each value array such as [1,2,3] or [3,4,5], in this case the integers 1 and 3, are what I need a unique against. so in the case of the last array, [1,1,1] and [1,2,3] would clash as the 1 is repeated.

What’s the best way to iterate through this type of nesting and signal true or false on whether there are duplicates?

Answer 1

def uniq_prime_elements?(arr)
  prime_elements = arr.map(&:first).map(&:first).compact
  prime_elements.length == prime_elements.uniq.length
end