My implementation of the Quicksort algorithm in Swift

Quicksort.swift

func quicksort<T: Comparable>(_ arr: [T]) -> [T] {
  guard arr.count > 1 else {
    return arr
  }
  
  let pivot = arr[arr.count / 2]
  var left  = [T]()
  var equal = [T]()
  var right = [T]()
  
  for i in 0 ..< arr.count {
    if arr[i] < pivot {
      left.append(arr[i])
    } else if arr[i] == pivot {
      equal.append(arr[i])
    } else {
      right.append(arr[i])
    }
  }
  return quicksort(left) + equal + quicksort(right)
}