[Python examples] QuickSort alogrithm explained

QuickSort, often abbreviated as qsort, is a widely-used sorting algorithm that employs the divide-and-conquer strategy. Here’s a succinct explanation and implementation in Python:

def quicksort(arr):
    # Base case: if the array has 1 or 0 elements, it's already sorted
    if len(arr) <= 1:
        return arr
    
    # Choose pivot element from the array
    pivot = arr[len(arr) // 2]
    
    # Divide array into 3 parts:
    # left: elements less than pivot
    # right: elements greater than pivot
    # middle: elements equal to pivot
    left = [x for x in arr if x < pivot]
    middle = [x for x in arr if x == pivot]
    right = [x for x in arr if x > pivot]
    
    # Recursive case:
    # Sort left and right parts and concatenate left, middle, and right
    return quicksort(left) + middle + quicksort(right)

Algorithm Explanation:

1. Base Case: If arr has 0 or 1 element, it's already sorted, return it.
2. Choose Pivot: Select an element, pivot, around which to partition the array.
3. Partition: Divide arr into three parts:
   • left: Elements smaller than pivot.
   • middle: Elements equal to pivot.
   • right: Elements larger than pivot.
4. Recursive Step: Recursively apply the steps to left and right.
5. Concatenate: Combine left, middle, and right.

This algorithm exhibits superior performance in many real-world data and is easy to implement, making it a popular choice among developers.

The code might slightly exceed 2000 characters when fully explained but provides a clear, concise depiction of QuickSort’s core logic and implementation in Python.