Binary Tree Paths

Author: anantkaushik

257-binary-tree-paths.py

@@ -0,0 +1,43 @@
+"""
+Problem Link: https://leetcode.com/problems/binary-tree-paths/
+
+Given the root of a binary tree, return all root-to-leaf paths in any order.
+A leaf is a node with no children.
+
+Example 1:
+
+Input: root = [1,2,3,null,5]
+Output: ["1->2->5","1->3"]
+
+Example 2:
+Input: root = [1]
+Output: ["1"]
+
+Constraints:
+The number of nodes in the tree is in the range [1, 100].
+-100 <= Node.val <= 100
+"""
+# 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 binaryTreePaths(self, root: Optional[TreeNode]) -> List[str]:
+ if not root:
+ return []
+ return self.helper(root, [], [])
+ 
+ def helper(self, root, res, cur_path):
+ if not root:
+ return res
+ 
+ cur_path.append(str(root.val))
+ if not root.left and not root.right:
+ res.append("->".join(cur_path))
+ 
+ self.helper(root.left, res, cur_path)
+ self.helper(root.right, res, cur_path)
+ cur_path.pop()
+ return res