Simple quick sort - Ruby

simple_quicksort.rb

# In Insertion sort, you simply went through each element in order and inserted it into a sorted sub-array. In this challenge, you cannot focus on one element at a time, but instead must deal with whole sub-arrays. Each time you call partition, you are sorting two parts of the array with respect to each other. Notice if you called partition on two elements, that sub-array would be fully sorted.
# Can you repeatedly call partition on each sub-array so that the entire array ends up sorted?
# In this challenge, print your array every time you finish your partitioning method, i.e. when you combine the partitioned array together. The first element in a sub-array should be used as a pivot. Partition the left side before partitioning the right side. Do not add the pivot to either side. Instead, put it in the middle when combining the two lists together.

def simple_quicksort(array)
  # write your code here
  # choose one > make two lists > loop the rest > if list bigger than 1 recurse > return all 
  pivot = array [0]
  smaller_than_pivot, bigger_than_pivot = [], []
  array.shift
  array.each do |el|
    if el<pivot then smaller_than_pivot.push(el)
    else bigger_than_pivot.push(el)
    end
  end
  smaller_than_pivot = simple_quicksort(smaller_than_pivot) if smaller_than_pivot.length>1
  bigger_than_pivot = simple_quicksort(bigger_than_pivot) if bigger_than_pivot.length>1
  result = [*smaller_than_pivot, pivot, *bigger_than_pivot]
  puts result.join(' ')
  return result
end