QuickSort.py

class QuickSort:
    def quicksort(self, list_a):
        self.helper(list_a, 0, len(list_a) - 1)

    def helper(self, list_a, first, last):
        if first < last:
            split_point = self.partition(list_a, first, last)
            self.helper(list_a, first, split_point - 1)
            self.helper(list_a, split_point + 1, last)

    def partition(self, list_a, first, last):
        pivot = list_a[first]
        left = first + 1
        right = last
        done = False
        while not done:
            while left <= right and list_a[left] <= pivot:
                left = left + 1

            while list_a[right] >= pivot and right >= left:
                right = right - 1

            if right < left:
                done = True
            else:
                temp = list_a[left]
                list_a[left] = list_a[right]
                list_a[right] = temp

        temp = list_a[first]
        list_a[first] = list_a[right]
        list_a[right] = temp

        return right


obj = QuickSort()
a = [5, 2, 4, 56, 7, 2, 43, 57]
obj.quicksort(a)
print(a)

# output = [2,2,4,5,7,43,56,57]