快速排序

def MySort(self , arr ):
        
        def QuickSort(arr, lo, hi):
            if lo >= hi:
                return
            
            p = Partition(arr, lo, hi)
            QuickSort(arr, lo, p-1)
            QuickSort(arr, p+1, hi)

        def Partition(arr, lo ,hi):
            if lo == hi:
                return lo
            pivot = arr[lo]
            left = lo 
            right = hi
            while(left < right):
                while arr[right] >= pivot and left < right:
                    right -= 1
                arr[left] = arr[right]
                while arr[left] <= pivot and left < right:
                    left += 1
                arr[right] = arr[left]
            
            arr[left] = pivot
            return left
        
        QuickSort(arr, 0, len(arr)-1)
        
        return arr