Solve 112. Path Sum

python/112_path_sum.py

@@ -0,0 +1,17 @@
+# Definition for a binary tree node.
+# 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: Optional[TreeNode], targetSum: int) -> bool:
+        def hasPathSumInner(root: Optional[TreeNode], currentSum: int) -> bool:
+            if root is None:
+                return False
+            elif root.left is None and root.right is None:
+                return currentSum + root.val == targetSum
+            else:
+                newSum = currentSum + root.val
+                return hasPathSumInner(root.left, newSum) or hasPathSumInner(root.right, newSum)
+        return hasPathSumInner(root, 0)