Merge Sort using Swift - iOS Coding Challenge

Complexity : O(n log n)

Let's Code :

//: A UIKit based Playground for presenting user interface

  

import UIKit

import Foundation

var sortThisArray : [Int] = [11,2,43,12,45,2,42,66,70,21,23,48,88,65,99,21]

func merge(left:[Int],right:[Int]) -> [Int] {

    var mergedArr : [Int] = []

    var left = left

    var right = right

    

    while left.count > 0 && right.count > 0 {

        if left.first! < right.first! {

            mergedArr.append(left.removeFirst())

        }

        else{

            mergedArr.append(right.removeFirst())

        }

    }

    return mergedArr + left + right

}

func mergeSort(array: [Int]) -> [Int]{

    var array = array

    guard array.count > 1 else {

        return array

    }

    let leftArr = Array(array[0..<array.count/2])

    let rightArr = Array(array[array.count/2..<array.count])

    

    return merge(left: mergeSort(array: leftArr), right: mergeSort(array: rightArr))

}

print("Initial Array Input : \(sortThisArray)")

sortThisArray = mergeSort(array: sortThisArray)

print("Array After Sorting : \(sortThisArray)")

Result