Improved BubbleSort and added Doctests (#443)

* BubbleSort | using alternativeBubbleSort() in it's implementation

Author: marsonya

Sorts/BubbleSort.js

@@ -1,11 +1,40 @@
-/* Bubble Sort is a algorithm to sort an array. It
-* compares adjacent element and swaps thier position
-* The big O on bubble sort in worst and best case is O(N^2).
- * Not efficient.
+/* Bubble Sort is an algorithm to sort an array. It
+*  compares adjacent element and swaps thier position
+*  The big O on bubble sort in worst and best case is O(N^2).
+*  Not efficient.
+*
+*  In bubble sort, we keep iterating while something was swapped in
+*  the previous inner-loop iteration. By swapped I mean, in the
+*  inner loop iteration, we check each number if the number proceeding
+*  it is greater than itself, if so we swap them.
+*
+*  Wikipedia: https://en.wikipedia.org/wiki/Bubble_sort
 */
 
+/*
+*  Doctests
+*
+*  > bubbleSort([5, 4, 1, 2, 3])
+*  [1, 2, 3, 4, 5]
+*  > bubbleSort([])
+*  []
+*  > bubbleSort([1, 2, 3])
+*  [1, 2, 3]
+*
+*  > alternativeBubbleSort([5, 4, 1, 2, 3])
+*  [1, 2, 3, 4, 5]
+*  > alternativeBubbleSort([])
+*  []
+*  > alternativeBubbleSort([1, 2, 3])
+*  [1, 2, 3]
+*/
+
+/*
+*  Using 2 for loops
+*/
 function bubbleSort (items) {
   const length = items.length
+
   for (let i = (length - 1); i > 0; i--) {
     // Number of passes
     for (let j = (length - i); j > 0; j--) {
@@ -16,31 +45,28 @@ function bubbleSort (items) {
       }
     }
   }
-}
-
-// Implementation of bubbleSort
 
-var ar = [5, 6, 7, 8, 1, 2, 12, 14]
-// Array before Sort
-console.log('-----before sorting-----')
-console.log(ar)
-bubbleSort(ar)
-// Array after sort
-console.log('-----after sorting-----')
-console.log(ar)
+  return items
+}
 
-/* alternative implementation of bubble sort algorithm.
- Using a while loop instead. For educational purposses only
- */
 /*
-*In bubble sort, we keep iterating while something was swapped in
-*the previous inner-loop iteration. By swapped I mean, in the
-*inner loop iteration, we check each number if the number proceeding
-*it is greater than itself, if so we swap them.
+*  Implementation of 2 for loops method
 */
+var array1 = [5, 6, 7, 8, 1, 2, 12, 14]
+// Before Sort
+console.log('\n- Before Sort | Implementation using 2 for loops -')
+console.log(array1)
+// After Sort
+console.log('- After Sort | Implementation using 2 for loops -')
+console.log(bubbleSort(array1))
+console.log('\n')
 
+/*
+*  Using a while loop and a for loop
+*/
 function alternativeBubbleSort (arr) {
   let swapped = true
+
   while (swapped) {
     swapped = false
     for (let i = 0; i < arr.length - 1; i++) {
@@ -50,12 +76,18 @@ function alternativeBubbleSort (arr) {
       }
     }
   }
+
   return arr
 }
 
-// test
-console.log('-----before sorting-----')
-var array = [10, 5, 3, 8, 2, 6, 4, 7, 9, 1]
-console.log(array)
-console.log('-----after sorting-----')
-console.log(alternativeBubbleSort(array))
+/*
+*  Implementation of a while loop and a for loop method
+*/
+var array2 = [5, 6, 7, 8, 1, 2, 12, 14]
+// Before Sort
+console.log('\n- Before Sort | Implementation using a while loop and a for loop -')
+console.log(array2)
+// After Sort
+console.log('- After Sort | Implementation using a while loop and a for loop -')
+console.log(alternativeBubbleSort(array2))
+console.log('\n')