diff --git a/src/my_project/interviews/amazon_high_frequency_23/round_2/two_sum_round_1.py b/src/my_project/interviews/amazon_high_frequency_23/round_2/two_sum_round_1.py
new file mode 100644
index 00000000..f3c376b0
--- /dev/null
+++ b/src/my_project/interviews/amazon_high_frequency_23/round_2/two_sum_round_1.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 v in dic_answer:
+                return [dic_answer[v], k]
+            
+            dic_answer[target - v] = k
+
+        return []
\ No newline at end of file
diff --git a/src/my_project/interviews/top_150_questions_round_21/valid_palindrome.py b/src/my_project/interviews/top_150_questions_round_21/valid_palindrome.py
new file mode 100644
index 00000000..82d11e04
--- /dev/null
+++ b/src/my_project/interviews/top_150_questions_round_21/valid_palindrome.py
@@ -0,0 +1,21 @@
+from typing import List, Union, Collection, Mapping, Optional
+from abc import ABC, abstractmethod
+import re
+
+class Solution:
+    def isPalindrome(self, s: str) -> bool:
+
+        # To lowercase
+        s = s.lower()
+
+        # Remove non-alphanumeric characters
+        s = re.sub(pattern='[^a-zA-Z0-9]', repl='', string=s)
+
+        # Determine if it is palindrome or not
+        len_s = len(s)
+
+        for i in range(len_s//2):
+            if s[i] != s[len_s - 1 -i]:
+                return False 
+            
+        return True 
\ No newline at end of file
diff --git a/tests/test_150_questions_round_21/test_valid_palindrome_round_21.py b/tests/test_150_questions_round_21/test_valid_palindrome_round_21.py
new file mode 100644
index 00000000..ac8ea509
--- /dev/null
+++ b/tests/test_150_questions_round_21/test_valid_palindrome_round_21.py
@@ -0,0 +1,15 @@
+import unittest
+from src.my_project.interviews.top_150_questions_round_21\
+.valid_palindrome import Solution
+
+class ValidPalindromeTestCase(unittest.TestCase):
+
+    def test_is_valid_palindrome(self):
+        solution = Solution()
+        output = solution.isPalindrome(s="A man, a plan, a canal: Panama")
+        self.assertTrue(output)
+
+    def test_is_no_valid_palindrome(self):
+        solution = Solution()
+        output = solution.isPalindrome(s="race a car")
+        self.assertFalse(output)
\ No newline at end of file