Add ruby quicksort

Author: szib

README.md

@@ -12,7 +12,7 @@ _Sorting algorithms implemented in different languages (for hacktoberfest_ 😃_
 | Java | [`Bead Sort`](Java/BeadSort.java) [`Bogo Sort`](Java/BogoSort.java) [`Bubble Sort`](Java/BubbleSort.java) <br> [`Counting Sort`](Java/Counting%20Sort.java) [`Heap Sort`](Java/HeapSort.java) [`Insertion Sort`](Java/InsertionSort.java) <br> [`Merge Sort`](Java/MergeSort.java) [`Quick Sort`](Java/QuickSort.java) [`Radix Sort`](Java/RadixSort.java) <br> [`Selection Sort`](Java/SelectionSort.java) [`Shell Sort`](Java/ShellSort.java) [`Tim Sort`](Java/TimSort.java) <br> [`Comb Sort`](Java/CombSort.java) [`Binary Insertion Sort`](Java/BinaryInsertionSort.java) [`Gnome Sort`](Java/GnomeSort.java) |
 | Javascript | [`Bogo Sort`](Javascript/bogoSort.js) [`Counting Sort`](Javascript/countingSort.js) [`Heap Sort`](Javascript/HeapSort.js) [`Insertion Sort`](Javascript/Insertionsort.js) [`Merge Sort`](Javascript/MergeSort.js) <br> [`Quick Sort`](Javascript/Quicksort.js) [`Bubble Sort`](Javascript/bubbleSort.js) [`Shell Sort`](Javascript/shellSort.js ) [`Selection Sort`](Javascript/selectionSort.js) <br> [`Radix Sort`](Javascript/RadixSort.js) |
 | Python | [`Bogo Sort`](Python/BogoSort.py) [`Bubble Sort`](Python/BubbleSort.py) [`Bucket Sort`](Python/BucketSort.py) <br> [`Gnome Sort`](Python/GnomeSort.py) [`Insertion Sort`](Python/InsertionSort.py) [`Merge Sort`](Python/MergeSort.py) <br> [`Quick Sort`](Python/QuickSort.py) [`Radix Sort`](Python/RadixSort.py) [`Selection Sort`](Python/SelectionSort.py) <br> [`Binary Insertion Sort`](Python/BinaryInsertionSort.py)  [`Heap Sort`](Python/heapSort.py) |
-| Ruby | [`Bubble Sort`](Ruby/bubble_sort.rb) [`Gnome Sort`](Ruby/gnome_sort.rb) [`Sort`](Ruby/sort.rb) [`Reverse sort`](Ruby/reverse.rb)
+| Ruby | [`Bubble Sort`](Ruby/bubble_sort.rb) [`Gnome Sort`](Ruby/gnome_sort.rb) [`Quick sort`](Ruby/quick_sort.rb) [`Sort`](Ruby/sort.rb) [`Reverse sort`](Ruby/reverse.rb)
 | Kotlin |[`Merge Sort`](Kotlin/MergeSort.kt) [`Bubble Sort`](Kotlin/BubbleSort.kt) [`Selection Sort`](Kotlin/selectionSort.kt) <br> [`Heap Sort`](Kotlin/HeapSort.kt) [`Insertion Sort`](Kotlin/InsertionSort.kt) [`Quick Sort`](Kotlin/QuickSort.kt) [`Bogo Sort`](Kotlin/BogoSort.kt)
 | Elixir | [`Selection Sort`](Elixir/selectionSort.exs)
 

Ruby/quick_sort.rb

@@ -0,0 +1,27 @@
+def quicksort(arr, left = 0, right = nil)
+  right = arr.length - 1 if right.nil?
+
+  if left < right
+    pivot = right
+
+    partition_index = partition(arr, pivot, left, right)
+
+    quicksort(arr, left, partition_index - 1)
+    quicksort(arr, partition_index + 1, right)
+  end
+  arr
+end
+
+def partition(arr, pivot, left, right)
+  pivot_value = arr[pivot]
+  index = left
+
+  (left..right).each do |i|
+    if arr[i] < pivot_value
+      arr[i], arr[index] = arr[index], arr[i]
+      index += 1
+    end
+  end
+  arr[right], arr[index] = arr[index], arr[right]
+  index
+end