Add Python type hints and doctests to other/two_sum.py (#2467)

* Add Python type hints and doctests to other/two_sum.py

#2465

* Update other/two_sum.py

Co-authored-by: Christian Clauss <cclauss@me.com>

* Update other/two_sum.py

Co-authored-by: Christian Clauss <cclauss@me.com>

* Update two_sum.py

Co-authored-by: Christian Clauss <cclauss@me.com>

other/two_sum.py

@@ -11,21 +11,37 @@ Given nums = [2, 7, 11, 15], target = 9,
 Because nums[0] + nums[1] = 2 + 7 = 9,
 return [0, 1].
 """
+from __future__ import annotations
 
 
-def twoSum(nums, target):
+def two_sum(nums: list[int], target: int) -> list[int]:
     """
-    :type nums: List[int]
-    :type target: int
-    :rtype: List[int]
+    >>> two_sum([2, 7, 11, 15], 9)
+    [0, 1]
+    >>> two_sum([15, 2, 11, 7], 13)
+    [1, 2]
+    >>> two_sum([2, 7, 11, 15], 17)
+    [0, 3]
+    >>> two_sum([7, 15, 11, 2], 18)
+    [0, 2]
+    >>> two_sum([2, 7, 11, 15], 26)
+    [2, 3]
+    >>> two_sum([2, 7, 11, 15], 8)
+    []
+    >>> two_sum([3 * i for i in range(10)], 19)
+    []
     """
     chk_map = {}
     for index, val in enumerate(nums):
         compl = target - val
         if compl in chk_map:
-            indices = [chk_map[compl], index]
-            print(indices)
-            return [indices]
-        else:
-            chk_map[val] = index
-    return False
+            return [chk_map[compl], index]
+        chk_map[val] = index
+    return []
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()
+    print(f"{two_sum([2, 7, 11, 15], 9) = }")