"""Robust Quicksort implementation with variations"""
import random

def quicksort(arr, low=0, high=None, pivot_strategy='last'):
    if high is None:
        high = len(arr) - 1
    if low < high:
        # Choose pivot based on strategy
        if pivot_strategy == 'random':
            pivot_index = random.randint(low, high)
            arr[pivot_index], arr[high] = arr[high], arr[pivot_index]
        elif pivot_strategy == 'median-of-three':
            mid = (low + high) // 2
            # Find median of arr[low], arr[mid], arr[high]
            s = sorted([(arr[low], low), (arr[mid], mid), (arr[high], high)], key=lambda x: x[0])
            median_index = s[1][1]
            arr[median_index], arr[high] = arr[high], arr[median_index]
        # Partition
        p = partition(arr, low, high)
        # Recursively sort partitions
        quicksort(arr, low, p - 1, pivot_strategy)
        quicksort(arr, p + 1, high, pivot_strategy)


def partition(arr, low, high):
    pivot = arr[high]
    i = low - 1
    for j in range(low, high):
        if arr[j] <= pivot:
            i += 1
            arr[i], arr[j] = arr[j], arr[i]
    arr[i + 1], arr[high] = arr[high], arr[i + 1]
    return i + 1

# Example usage
if __name__ == "__main__":
    data = [3, 6, 8, 10, 1, 2, 1, 5, 9, 4]
    print("Original data:", data)
    quicksort(data, pivot_strategy='median-of-three')
    print("Sorted data:", data)