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Swapsort algorithm and corresponding tests #1152

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Oct 13, 2022
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31 changes: 31 additions & 0 deletions Sorts/SwapSort.js
Original file line number Diff line number Diff line change
@@ -0,0 +1,31 @@
/**
* @function SwapSort
* @description Swap Sort is an algorithm to find the number of swaps required to sort an array.
Time complexity of Swap Sort Algorithm is O(nlogn).
Auxiliary Space required for Swap Sort Algorithm is O(n).
* @param {Integer[]} items - Array of integers
* @return {Integer} - Number of swaps required to sort the array.
* @see [SwapSort](https://www.geeksforgeeks.org/minimum-number-swaps-required-sort-array/)
*/

export function minSwapsToSort (items) {
const sortedArray = items.slice()
sortedArray.sort()
const indexMap = {}
for (let i = 0; i < items.length; i++) {
indexMap[items[i]] = i
}
let swaps = 0
for (let i = 0; i < items.length; i++) {
if (items[i] !== sortedArray[i]) {
const temp = items[i]
items[i] = items[indexMap[sortedArray[i]]]
items[indexMap[sortedArray[i]]] = temp

indexMap[temp] = indexMap[sortedArray[i]]
indexMap[sortedArray[i]] = i
swaps++
}
}
return swaps
}
18 changes: 18 additions & 0 deletions Sorts/test/SwapSort.test.js
Original file line number Diff line number Diff line change
@@ -0,0 +1,18 @@
import { minSwapsToSort } from '../SwapSort'

describe('SwapSort', () => {
it('should work for empty arrays', () => {
expect(minSwapsToSort([])).toEqual(0)
})

it('should work for sorted arrays', () => {
expect(minSwapsToSort([1, 2, 3, 4, 5, 6])).toEqual(0)
})

it('should return correct results', () => {
expect(minSwapsToSort([7, 6, 2, 5, 11, 0])).toEqual(2)
expect(minSwapsToSort([3, 3, 2, 1, 0])).toEqual(2)
expect(minSwapsToSort([3, 0, 2, 1, 9, 8, 7, 6])).toEqual(4)
expect(minSwapsToSort([1, 0, 14, 0, 8, 6, 8])).toEqual(3)
})
})