Merge pull request #149 from kavienanj/sorting

Add Insertion Sort file #2

Author: DeepNinja07x

Diff for: Algorithms/insertion_sort.py

@@ -0,0 +1,60 @@
+"""
+A pure Python implementation of the insertion sort algorithm
+
+This algorithm sorts a collection by comparing adjacent elements.
+When it finds that order is not respected, it moves the element compared
+backward until the order is correct.  It then goes back directly to the
+element's initial position resuming forward comparison.
+
+For doctests run following command:
+python3 -m doctest -v insertion_sort.py
+
+For manual testing run:
+python3 insertion_sort.py
+"""
+
+
+def insertion_sort(collection: list) -> list:
+    """A pure Python implementation of the insertion sort algorithm
+
+    :param collection: some mutable ordered collection with heterogeneous
+    comparable items inside
+    :return: the same collection ordered by ascending
+
+    Examples:
+    >>> insertion_sort([0, 5, 3, 2, 2])
+    [0, 2, 2, 3, 5]
+    >>> insertion_sort([]) == sorted([])
+    True
+    >>> insertion_sort([-2, -5, -45]) == sorted([-2, -5, -45])
+    True
+    >>> insertion_sort(['d', 'a', 'b', 'e', 'c']) == sorted(['d', 'a', 'b', 'e', 'c'])
+    True
+    >>> import random
+    >>> collection = random.sample(range(-50, 50), 100)
+    >>> insertion_sort(collection) == sorted(collection)
+    True
+    >>> import string
+    >>> collection = random.choices(string.ascii_letters + string.digits, k=100)
+    >>> insertion_sort(collection) == sorted(collection)
+    True
+    """
+
+    for insert_index, insert_value in enumerate(collection[1:]):
+        temp_index = insert_index
+        while insert_index >= 0 and insert_value < collection[insert_index]:
+            collection[insert_index + 1] = collection[insert_index]
+            insert_index -= 1
+        if insert_index != temp_index:
+            collection[insert_index + 1] = insert_value
+    return collection
+
+
+if __name__ == "__main__":
+    from doctest import testmod
+
+    testmod()
+
+    user_input = input("Enter numbers separated by a comma:\n").strip()
+    unsorted = [int(item) for item in user_input.split(",")]
+    print(f"{insertion_sort(unsorted) = }")