Fix wiggle sort #991

Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,36 @@
	/*
	* Wiggle sort sorts the array into a wave like array.
	* An array ‘arr[0..n-1]’ is sorted in wave form if arr[0] <= arr[1] >= arr[2] <= arr[3] >= arr[4] <= .....
	* KEEP IN MIND: there are also more strict definitions of wiggle sort which use
	* the rule arr[0] < arr[1] > arr[2] < arr[3] > arr[4] < ... but this function
	* allows for equality of values next to each other.
	*/
	import { quickSelectSearch } from '../Search/QuickSelectSearch.js'

	export const simplifiedWiggleSort = function (arr) {
	// find Median using QuickSelect
	let median = quickSelectSearch(arr, Math.floor(arr.length / 2.0))
	median = median[Math.floor(arr.length / 2.0)]

	const sorted = new Array(arr.length)

	let smallerThanMedianIndx = 0
	let greaterThanMedianIndx = arr.length - 1 - (arr.length % 2)

	for (let i = 0; i < arr.length; i++) {
	if (arr[i] > median) {
	sorted[greaterThanMedianIndx] = arr[i]
	greaterThanMedianIndx -= 2
	} else {
	if (smallerThanMedianIndx < arr.length) {
	sorted[smallerThanMedianIndx] = arr[i]
	smallerThanMedianIndx += 2
	} else {
	sorted[greaterThanMedianIndx] = arr[i]
	greaterThanMedianIndx -= 2
	}
	}
	}

	return sorted
	}

21 changes: 0 additions & 21 deletions Sorts/WiggleSort.js

Show comments View file Open in desktop

This file was deleted.

24 changes: 24 additions & 0 deletions Sorts/test/SimplifiedWiggleSort.test.js

Show comments View file Open in desktop

Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,24 @@
	import { simplifiedWiggleSort } from '../SimplifiedWiggleSort.js'

	describe('simplified wiggle sort', () => {
	test('simplified wiggle sort for chars', () => {
	const src = ['a', 'b', 'c']
	expect(simplifiedWiggleSort(src)).toEqual(['a', 'c', 'b'])
	})

	test('wiggle sort with duplicates, even array', () => {
	const src = [2, 2, 1, 3]
	expect(simplifiedWiggleSort(src)).toEqual([1, 3, 2, 2])
	})

	test('wiggle sort with duplicates, odd array', () => {
	const src = [1, 1, 1, 2, 4]
	expect(simplifiedWiggleSort(src)).toEqual([1, 4, 1, 2, 1])
	})

	test('simplified wiggle sort which leads to equal values next to ' +
	'each other', () => {
	const src = [3, 3, 5, 1]
	expect(simplifiedWiggleSort(src)).toEqual([1, 5, 3, 3])
	})
	})

Navigation Menu