diff --git a/src/algorithms/sorting/cocktail-shaker-sort/CocktailShakerSort.js b/src/algorithms/sorting/cocktail-shaker-sort/CocktailShakerSort.js new file mode 100644 index 00000000..f5755a2f --- /dev/null +++ b/src/algorithms/sorting/cocktail-shaker-sort/CocktailShakerSort.js @@ -0,0 +1,59 @@ +import Sort from '../Sort'; + +export default class CocktailShakerSort extends Sort { + sort(originalArray) { + // Flag that holds info about whether the swap has occur or not. + let swapped = true; + // Clone original array to prevent its modification. + const array = [...originalArray]; + + let start = 0; + let end = array.length; + + while (swapped) { + // Reset the swapped flag on entering the loop, + // because it might be true from a previous iteration. + swapped = false; + + // Loop forward same as the bubble sort + for (let i = start; i < end - 1; i += 1) { + // Call visiting callback. + this.callbacks.visitingCallback(array[i]); + + if (this.comparator.greaterThan(array[i], array[i + 1])) { + [array[i], array[i + 1]] = [array[i + 1], array[i]]; + swapped = true; + } + } + + // Move the end point backward by one, + // because the item at the end point is already in its correct position. + end -= 1; + + // If nothing swapped, then array is sorted. + if (swapped === false) { + break; + } + + // Reset the swapped flag so that it can be used in the next stage + swapped = false; + + // Loop backward, doing the same comparison as in the previous stage + for (let i = end - 1; i >= start; i -= 1) { + // Call visiting callback. + this.callbacks.visitingCallback(array[i]); + + if (this.comparator.greaterThan(array[i], array[i + 1])) { + [array[i], array[i + 1]] = [array[i + 1], array[i]]; + swapped = true; + } + } + + // Move the start point forward by one, + // because the item at the start point is already in its correct position. + start += 1; + + } + return array; + } +} diff --git a/src/algorithms/sorting/cocktail-shaker-sort/README.md b/src/algorithms/sorting/cocktail-shaker-sort/README.md new file mode 100644 index 00000000..11769e26 --- /dev/null +++ b/src/algorithms/sorting/cocktail-shaker-sort/README.md @@ -0,0 +1,23 @@ +# Cocktail Shaker Sort + +_Read this in other languages:_ +[_简体中文_](README.zh-CN.md) + +Cocktail Shaker Sort is an algorithm that is a Bidirectional Bubble Sort. + +The algorithm extends bubble sort by operating in two directions. +While it improves on bubble sort by more quickly moving items to the beginning of the list, it provides only marginal performance improvements. + +![Algorithm Visualization](https://upload.wikimedia.org/wikipedia/commons/e/ef/Sorting_shaker_sort_anim.gif) + +## Complexity + +| Name | Best | Average | Worst | Memory | Stable | Comments | +| ------------------------------ | :-------------: | :-----------------: | :-----------------: | :-------: | :-------: | :-------- | +| **Cocktail Shaker Sort** | n | n2 | n2 | 1 | Yes | | + +## References + +- [Cocktail Shaker Sort on Wikipedia](https://en.wikipedia.org/wiki/Cocktail_shaker_sort) + +- [Bubble Sort on Wikipedia](https://en.wikipedia.org/wiki/Bubble_sort) diff --git a/src/algorithms/sorting/cocktail-shaker-sort/README.zh-CN.md b/src/algorithms/sorting/cocktail-shaker-sort/README.zh-CN.md new file mode 100644 index 00000000..2101a911 --- /dev/null +++ b/src/algorithms/sorting/cocktail-shaker-sort/README.zh-CN.md @@ -0,0 +1,23 @@ +# 鸡尾酒排序 + +_Read this in other languages:_ +[_English_](README.md) + +鸡尾酒排序是一种双向气泡排序的算法。 + +该算法通过在两个方向上操作扩展了冒泡排序。虽然它通过更快速地将项目移到列表的开头而改进了冒泡排序，但它只提供了微弱的性能改进。 + +![Algorithm Visualization](https://upload.wikimedia.org/wikipedia/commons/e/ef/Sorting_shaker_sort_anim.gif) + + +## 复杂度 + +| 名称 | 最优 | 平均 | 最坏 | 内存 | 稳定 | 备注 | +| ------------------------------ | :-------------: | :-----------------: | :-----------------: | :-------: | :-------: | :-------- | +| **鸡尾酒排序** | n | n2 | n2 | 1 | 是 | | + +## 参考 + +- [鸡尾酒排序(维基百科)](https://zh.wikipedia.org/wiki/%E9%B8%A1%E5%B0%BE%E9%85%92%E6%8E%92%E5%BA%8F) + +- [冒泡排序(维基百科)](https://zh.wikipedia.org/wiki/%E5%86%92%E6%B3%A1%E6%8E%92%E5%BA%8F) \ No newline at end of file diff --git a/src/algorithms/sorting/cocktail-shaker-sort/__test__/CocktailShakerSort.test.js b/src/algorithms/sorting/cocktail-shaker-sort/__test__/CocktailShakerSort.test.js new file mode 100644 index 00000000..17cdea5e --- /dev/null +++ b/src/algorithms/sorting/cocktail-shaker-sort/__test__/CocktailShakerSort.test.js @@ -0,0 +1,64 @@ +import CocktailShakerSort from '../CocktailShakerSort'; +import { + equalArr, + notSortedArr, + reverseArr, + sortedArr, + SortTester, +} from '../../SortTester'; + +// Complexity constants. +const SORTED_ARRAY_VISITING_COUNT = 19; +const NOT_SORTED_ARRAY_VISITING_COUNT = 159; +const REVERSE_SORTED_ARRAY_VISITING_COUNT = 200; +const EQUAL_ARRAY_VISITING_COUNT = 19; + +describe('CocktailShakerSort', () => { + it('should sort array', () => { + SortTester.testSort(CocktailShakerSort); + }); + + it('should sort array with custom comparator', () => { + SortTester.testSortWithCustomComparator(CocktailShakerSort); + }); + + it('should do stable sorting', () => { + SortTester.testSortStability(CocktailShakerSort); + }); + + it('should sort negative numbers', () => { + SortTester.testNegativeNumbersSort(CocktailShakerSort); + }); + + it('should visit EQUAL array element specified number of times', () => { + SortTester.testAlgorithmTimeComplexity( + CocktailShakerSort, + equalArr, + EQUAL_ARRAY_VISITING_COUNT, + ); + }); + + it('should visit SORTED array element specified number of times', () => { + SortTester.testAlgorithmTimeComplexity( + CocktailShakerSort, + sortedArr, + SORTED_ARRAY_VISITING_COUNT, + ); + }); + + it('should visit NOT SORTED array element specified number of times', () => { + SortTester.testAlgorithmTimeComplexity( + CocktailShakerSort, + notSortedArr, + NOT_SORTED_ARRAY_VISITING_COUNT, + ); + }); + + it('should visit REVERSE SORTED array element specified number of times', () => { + SortTester.testAlgorithmTimeComplexity( + CocktailShakerSort, + reverseArr, + REVERSE_SORTED_ARRAY_VISITING_COUNT, + ); + }); +});