Swapsort algorithm and corresponding tests (TheAlgorithms#1152)

Author: chnlmshr

Sorts/SwapSort.js

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+/**
+ * @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
+}

Sorts/test/SwapSort.test.js

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+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)
+  })
+})