diff --git a/src/my_project/interviews/top_150_questions_round_20/two_sum.py b/src/my_project/interviews/top_150_questions_round_20/two_sum.py
new file mode 100644
index 00000000..0637b46e
--- /dev/null
+++ b/src/my_project/interviews/top_150_questions_round_20/two_sum.py
@@ -0,0 +1,16 @@
+from typing import List, Union, Collection, Mapping, Optional
+from abc import ABC, abstractmethod
+
+class Solution:
+    def twoSum(self, nums: List[int], target: int) -> List[int]:
+
+        dic_answer = dict()
+
+        for k, v in enumerate(nums):
+
+            if not v in dic_answer:
+                dic_answer[target - v] = k
+            else: 
+                return [dic_answer[v], k]
+            
+        return -1
\ No newline at end of file
diff --git a/tests/test_150_questions_round_20/test_two_sum_round_20.py b/tests/test_150_questions_round_20/test_two_sum_round_20.py
new file mode 100644
index 00000000..7ba73b96
--- /dev/null
+++ b/tests/test_150_questions_round_20/test_two_sum_round_20.py
@@ -0,0 +1,18 @@
+import unittest
+from src.my_project.interviews.top_150_questions_round_20\
+.two_sum import Solution
+
+class TwoSumTestCase(unittest.TestCase):
+
+    def test_is_two_sum(self):
+        solution = Solution()
+        output = solution.twoSum(nums=[2,7,11,15], target=9)
+        target = [0,1]
+        for k, v in enumerate(target):
+            self.assertEqual(v, output[k])
+
+    def test_is_no_two_sum(self):
+        solution = Solution()
+        output = solution.twoSum(nums=[2,7,11,15], target=0)
+        target = -1
+        self.assertEqual(output, target)
\ No newline at end of file