Create quicksort.py

divide_and_conquer/quicksort.py

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+from __future__ import annotations
+
+
+def quicksort(array: list) -> list:
+    """
+    Returns a sorted list using the quicksort algorithm.
+
+    Quicksort uses a divide-and-conquer approach to sort the elements
+    by selecting a pivot and partitioning the array.
+
+    >>> quicksort([-2, 3, -10, 11, 99, 100000, 100, -200])
+    [-200, -10, -2, 3, 11, 99, 100, 100000]
+
+    >>> quicksort([1, 2, 3, 4, 5])
+    [1, 2, 3, 4, 5]
+
+    >>> quicksort([5, 4, 3, 2, 1])
+    [1, 2, 3, 4, 5]
+
+    >>> quicksort([-200])
+    [-200]
+
+    >>> quicksort([])
+    []
+
+    >>> quicksort([10000000, 1, -1111111111, 101111111112, 9000002])
+    [-1111111111, 1, 9000002, 10000000, 101111111112]
+
+    >>> quicksort([2, 1])
+    [1, 2]
+    """
+    if len(array) <= 1:
+        return array
+
+    pivot = array[-1]  # Choose the last element as the pivot
+    left = [x for x in array[:-1] if x <= pivot]
+    right = [x for x in array[:-1] if x > pivot]
+
+    return [*quicksort(left), pivot, *quicksort(right)]
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()