diff --git a/src/my_project/interviews/amazon_high_frequency_23/round_2/two_sum_round_2.py b/src/my_project/interviews/amazon_high_frequency_23/round_2/two_sum_round_2.py
new file mode 100644
index 00000000..c89ef2f0
--- /dev/null
+++ b/src/my_project/interviews/amazon_high_frequency_23/round_2/two_sum_round_2.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]:
+
+        answer = dict()
+
+        for k,v in enumerate(nums):
+
+            if v in answer:
+                return [answer[v], k]
+            else: 
+                answer[target - v] = k
+
+        return []
\ No newline at end of file
diff --git a/src/my_project/interviews/amazon_high_frequency_23/round_2/valid_palindrome_round_5.py b/src/my_project/interviews/amazon_high_frequency_23/round_2/valid_palindrome_round_5.py
new file mode 100644
index 00000000..8af6a65e
--- /dev/null
+++ b/src/my_project/interviews/amazon_high_frequency_23/round_2/valid_palindrome_round_5.py
@@ -0,0 +1,21 @@
+from typing import List, Union, Collection, Mapping, Optional
+from abc import ABC, abstractmethoda
+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
diff --git a/src/my_project/interviews/top_150_questions_round_21/is_subsequence.py b/src/my_project/interviews/top_150_questions_round_21/is_subsequence.py
new file mode 100644
index 00000000..9ce6ee1b
--- /dev/null
+++ b/src/my_project/interviews/top_150_questions_round_21/is_subsequence.py
@@ -0,0 +1,18 @@
+from typing import List, Union, Collection, Mapping, Optional
+from abc import ABC, abstractmethod
+
+class Solution:
+    def isSubsequence(self, s: str, t: str) -> bool:
+
+        l1, l2 = 0, 0
+
+        len_s, len_t = len(s), len(t)
+
+        while l1 < len_s and l2 < len_t:
+
+            if s[l1] == t[l2]:
+                l1 += 1
+            
+            l2 += 1
+
+        return l1 == len_s
\ No newline at end of file
diff --git a/tests/test_150_questions_round_21/test_is_subsequence_round_21.py b/tests/test_150_questions_round_21/test_is_subsequence_round_21.py
new file mode 100644
index 00000000..5a78d7e3
--- /dev/null
+++ b/tests/test_150_questions_round_21/test_is_subsequence_round_21.py
@@ -0,0 +1,15 @@
+import unittest
+from src.my_project.interviews.top_150_questions_round_21\
+.is_subsequence import Solution
+
+class IsSubsequenceTestCase(unittest.TestCase):
+
+    def test_is_subsequence(self):
+        solution = Solution()
+        output = solution.isSubsequence(s="abc", t="ahbgdc")
+        self.assertTrue(output)
+
+    def test_is_no_subsequence(self):
+        solution = Solution()
+        output = solution.isSubsequence(s="axc", t="ahbgdc")
+        self.assertFalse(output)
\ No newline at end of file