adding path sum algo

src/my_project/interviews/top_150_questions_round_11/path_sum.py

@@ -0,0 +1,21 @@
+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 hasPathSum(self, root: TreeNode, targetSum: int) -> bool:
+
+        if not root: 
+            return False 
+        elif not root.left and not root.right and root.val == targetSum: 
+            return True 
+        else: 
+            temp_target = targetSum - root.val 
+            return self.hasPathSum(root.left, temp_target) \
+                   or self.hasPathSum(root.right, temp_target)

tests/test_150_questions_round_11/test_path_sum_round_11.py

@@ -0,0 +1,18 @@
+import unittest 
+from src.my_project.interviews.top_150_questions_round_11\
+.path_sum import TreeNode, Solution
+
+
+class HasPathSumTestCase(unittest.TestCase):
+
+    def test_is_path_sum(self):
+        solution = Solution()
+        tree = TreeNode(1, TreeNode(2), TreeNode(3))
+        output = solution.hasPathSum(root=tree, targetSum=3)
+        self.assertTrue(output)
+
+    def test_is_no_path_sum(self):
+            solution = Solution()
+            tree = TreeNode(1, TreeNode(2), TreeNode(3))
+            output = solution.hasPathSum(root=tree, targetSum=10)
+            self.assertFalse(output)