快速排序 swift

func quickSort<T: Comparable>(_ array: [T]) -> [T] {
    guard array.count > 1 else { return array }
    let pivot = array[array.count / 2]
    let less = array.filter { $0 < pivot }
    let equal = array.filter { $0 == pivot }
    let greater = array.filter { $0 > pivot }
    return quickSort(less) + equal + quickSort(greater)
}