diff --git a/src/my_project/interviews/amazon_high_frequency_23/common_algos/two_sum_round_2.py b/src/my_project/interviews/amazon_high_frequency_23/common_algos/two_sum_round_2.py
new file mode 100644
index 00000000..c7f907c0
--- /dev/null
+++ b/src/my_project/interviews/amazon_high_frequency_23/common_algos/two_sum_round_2.py
@@ -0,0 +1,21 @@
+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 []
+
+
+
+        
+
diff --git a/src/my_project/interviews/amazon_high_frequency_23/common_algos/valid_palindrome_round_2.py b/src/my_project/interviews/amazon_high_frequency_23/common_algos/valid_palindrome_round_2.py
new file mode 100644
index 00000000..fa21021b
--- /dev/null
+++ b/src/my_project/interviews/amazon_high_frequency_23/common_algos/valid_palindrome_round_2.py
@@ -0,0 +1,22 @@
+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=r'[^a-zA-Z0-9]', repl='', string=s)
+
+        # Determine if s 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_22/ex_122_number_of_1_bits.py b/src/my_project/interviews/top_150_questions_round_22/ex_122_number_of_1_bits.py
new file mode 100644
index 00000000..eafdab14
--- /dev/null
+++ b/src/my_project/interviews/top_150_questions_round_22/ex_122_number_of_1_bits.py
@@ -0,0 +1,6 @@
+from typing import List, Union, Collection, Mapping, Optional
+from abc import ABC, abstractmethod
+
+class Solution:
+    def hammingWeight(self, n: int) -> int: 
+        return bin(n).count('1')
diff --git a/src/my_project/interviews/top_150_questions_round_22/ex_123_single_number.py b/src/my_project/interviews/top_150_questions_round_22/ex_123_single_number.py
new file mode 100644
index 00000000..6751e0d3
--- /dev/null
+++ b/src/my_project/interviews/top_150_questions_round_22/ex_123_single_number.py
@@ -0,0 +1,12 @@
+from typing import List, Union, Collection, Mapping, Optional
+from abc import ABC, abstractmethod
+
+class Solution:
+    def singleNumber(self, nums: List[int]) -> int:
+
+        answer = 0
+
+        for num in nums:
+            answer ^= num
+
+        return answer
\ No newline at end of file
diff --git a/src/my_project/interviews_typescript/top_150_questions_round_1/ex_122_number_of_1_bits.ts b/src/my_project/interviews_typescript/top_150_questions_round_1/ex_122_number_of_1_bits.ts
new file mode 100644
index 00000000..e6e7e8d4
--- /dev/null
+++ b/src/my_project/interviews_typescript/top_150_questions_round_1/ex_122_number_of_1_bits.ts
@@ -0,0 +1,8 @@
+function hammingWeight(n: number): number {
+    let count = 0;
+    while (n !== 0) {
+        count += n & 1;
+        n >>>= 1;
+    }
+    return count;
+};
\ No newline at end of file
diff --git a/src/my_project/interviews_typescript/top_150_questions_round_1/ex_123_single_number.ts b/src/my_project/interviews_typescript/top_150_questions_round_1/ex_123_single_number.ts
new file mode 100644
index 00000000..abb40cc5
--- /dev/null
+++ b/src/my_project/interviews_typescript/top_150_questions_round_1/ex_123_single_number.ts
@@ -0,0 +1,3 @@
+function singleNumber(nums: number[]): number {
+    return nums.reduce((acc, n) => acc ^ n, 0);
+};
\ No newline at end of file
diff --git a/tests/test_150_questions_round_22/test_122_number_of_1_bits_round_22.py b/tests/test_150_questions_round_22/test_122_number_of_1_bits_round_22.py
new file mode 100644
index 00000000..bd101780
--- /dev/null
+++ b/tests/test_150_questions_round_22/test_122_number_of_1_bits_round_22.py
@@ -0,0 +1,11 @@
+import unittest
+from src.my_project.interviews.top_150_questions_round_22\
+.ex_122_number_of_1_bits import Solution
+
+class NumberOfOnesTestCase(unittest.TestCase):
+
+    def test_number_of_ones(self):
+        solution = Solution()
+        output = solution.hammingWeight(n=11)
+        target = 3
+        self.assertEqual(output, target)
\ No newline at end of file
diff --git a/tests/test_150_questions_round_22/test_123_single_number_round_22.py b/tests/test_150_questions_round_22/test_123_single_number_round_22.py
new file mode 100644
index 00000000..41bc5176
--- /dev/null
+++ b/tests/test_150_questions_round_22/test_123_single_number_round_22.py
@@ -0,0 +1,11 @@
+import unittest
+from src.my_project.interviews.top_150_questions_round_22\
+.ex_123_single_number import Solution
+
+class SingleNumberTestCase(unittest.TestCase):
+
+    def test_single_number(self):
+        solution = Solution()
+        output = solution.singleNumber(nums=[2,2,1])
+        target = 1 
+        self.assertEqual(output, target)
\ No newline at end of file