Pseudo Code

quickSort(array):
   if length(array) <= 1:
      return array
   pivot = last element of array
   less = elements (except pivot) that are < pivot
   rest = elements (except pivot) that are >= pivot
   return quickSort(less) + [pivot] + quickSort(rest)

How it maps to the idea:

• pivot is the element we compare everything against. Here it is always the last element.
• less collects every element smaller than the pivot; rest collects the others.
• Recursively sorting less and rest and placing the pivot between them yields a fully sorted array, because everything in less belongs before the pivot and everything in rest belongs after it.