Merge pull request trekhleb#10 from albertstill/improve-bubble-sort

stop bubble sort revisiting already sorted elements

Author: trekhleb

src/algorithms/sorting/bubble-sort/BubbleSort.js

@@ -7,13 +7,13 @@ export default class BubbleSort extends Sort {
     // Clone original array to prevent its modification.
     const array = [...originalArray];
 
-    for (let i = 0; i < array.length; i += 1) {
+    for (let i = 1; i < array.length; i += 1) {
       swapped = false;
 
       // Call visiting callback.
       this.callbacks.visitingCallback(array[i]);
 
-      for (let j = 0; j < array.length - 1; j += 1) {
+      for (let j = 0; j < array.length - i; j += 1) {
         // Call visiting callback.
         this.callbacks.visitingCallback(array[j]);
 

src/algorithms/sorting/bubble-sort/__test__/BubbleSort.test.js

@@ -9,8 +9,8 @@ import {
 
 // Complexity constants.
 const SORTED_ARRAY_VISITING_COUNT = 20;
-const NOT_SORTED_ARRAY_VISITING_COUNT = 280;
-const REVERSE_SORTED_ARRAY_VISITING_COUNT = 400;
+const NOT_SORTED_ARRAY_VISITING_COUNT = 189;
+const REVERSE_SORTED_ARRAY_VISITING_COUNT = 209;
 const EQUAL_ARRAY_VISITING_COUNT = 20;
 
 describe('BubbleSort', () => {