Create exchange_sort.py (#4600)

* Create exchange_sort.py

added exchange sort

* Fixed doctest in exchange_sort.py

* Fixed formatting error and added new length variable

added empty line at end of exchange_sort.py and turned len(numbers) into a variable

* Fixed formatting errors with black

added empty line

sorts/exchange_sort.py

@@ -0,0 +1,27 @@
+def exchange_sort(numbers: list[int]) -> list[int]:
+    """
+    Uses exchange sort to sort a list of numbers.
+    Source: https://en.wikipedia.org/wiki/Sorting_algorithm#Exchange_sort
+    >>> exchange_sort([5, 4, 3, 2, 1])
+    [1, 2, 3, 4, 5]
+    >>> exchange_sort([-1, -2, -3])
+    [-3, -2, -1]
+    >>> exchange_sort([1, 2, 3, 4, 5])
+    [1, 2, 3, 4, 5]
+    >>> exchange_sort([0, 10, -2, 5, 3])
+    [-2, 0, 3, 5, 10]
+    >>> exchange_sort([])
+    []
+    """
+    numbers_length = len(numbers)
+    for i in range(numbers_length):
+        for j in range(i + 1, numbers_length):
+            if numbers[j] < numbers[i]:
+                numbers[i], numbers[j] = numbers[j], numbers[i]
+    return numbers
+
+
+if __name__ == "__main__":
+    user_input = input("Enter numbers separated by a comma:\n").strip()
+    unsorted = [int(item) for item in user_input.split(",")]
+    print(exchange_sort(unsorted))