adding algo

src/my_project/interviews/amazon_high_frequency_23/common_algos/two_sum_round_4.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 []

src/my_project/interviews/amazon_high_frequency_23/common_algos/valid_palindrome_round_4.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 

src/my_project/interviews/top_150_questions_round_22/ex_77_count_complete_tree_nodes.py

@@ -0,0 +1,17 @@
+from typing import List, Union, Collection, Mapping, Optional
+from abc import ABC, abstractmethod
+
+class TreeNode:
+    def __init__(self, val=0, left=None, right=None):
+        self.val = val
+        self.left = left
+        self.right = right
+
+class Solution:
+    def countNodes(self, root: Optional[TreeNode]) -> int:
+
+        if not root:
+            return 0
+        else: 
+            return self.countNodes(root.left) + self.countNodes(root.right) + 1
+

src/my_project/interviews_typescript/top_150_questions_round_1/ex_77_count_complete_tree_nodes.ts

@@ -0,0 +1,9 @@
+import { TreeNode } from './TreeNode';                    
+
+function countNodes(root: TreeNode | null): number {
+    if (!root) {
+        return 0;
+    } else {
+        return countNodes(root.left) + countNodes(root.right) + 1;
+    }
+}

tests/test_150_questions_round_22/test_77_count_complete_tree_nodes_round_22.py

@@ -0,0 +1,20 @@
+import unittest
+from typing import Optional, List
+from src.my_project.interviews.top_150_questions_round_22\
+.ex_77_count_complete_tree_nodes import Solution, TreeNode
+
+
+class CountNodesTestCase(unittest.TestCase):
+
+    def test_count_none(self):
+        solution = Solution()
+        tree = None 
+        output = solution.countNodes(root=tree)
+        self.assertEqual(0, output)
+
+
+    def test_count_non_empty_tree(self):
+        solution = Solution()
+        tree = TreeNode(1, TreeNode(2), TreeNode(3))
+        output = solution.countNodes(root=tree)
+        self.assertEqual(3, output)