Merge Sort in Swift

MergeSort.swift

func sort(_ array: [Int]) -> [Int] {
    guard array.count > 1 else {
        return array
    }

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

    return merge(sort(left), sort(right))
}

func merge(_ arrayOne: [Int], _ arrayTwo: [Int]) -> [Int] {
    var merged: [Int] = []
    var left = arrayOne
    var right = arrayTwo

    while left.count > 0 && right.count > 0 {
        if left.first! < right.first! {
            merged.append(left.removeFirst())
        } else {
            merged.append(right.removeFirst())
        }
    }

    return merged + left + right
}


print(sort([1, 5, 2, 4, 6]))