关于快排 quicksort 的两种写法

写法 1 i = low 返回 low

def partition(arr,low,high): 
    i = low      # index of smaller element 
    pivot = arr[high]     # pivot
    for j in range(low , high): 
        if   arr[j] <= pivot:
            arr[i],arr[j] = arr[j],arr[i] 
            i = i+1
    arr[i],arr[high] = arr[high],arr[i] 
    return i

def quickSort(arr,low,high): 
    if low < high: 
        pi = partition(arr,low,high) 
        quickSort(arr, low, pi-1) 
        quickSort(arr, pi+1, high) 

写法 2 i = (low-1)开始 返回 i + 1

def partition(arr,low,high): 
    i = ( low-1 )         # index of smaller element 
    pivot = arr[high]     # pivot 
  
    for j in range(low , high): 
        if   arr[j] <= pivot: 
            i = i+1 
            arr[i],arr[j] = arr[j],arr[i] 
  
    arr[i+1],arr[high] = arr[high],arr[i+1] 
    return ( i+1 ) 
  
def quickSort(arr,low,high): 
    if low < high: 
        pi = partition(arr,low,high) 
        quickSort(arr, low, pi-1) 
        quickSort(arr, pi+1, high)