#144

Binary Tree Preorder Traversal

newbie · 220 · lc easy +17 · 75.3% accepted · 8,842 likes · top 86%

Description

Given the root of a binary tree, return its node values collected in preorder (root, then left subtree, then right subtree).

Code

# 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 preorderTraversal(self, root: Optional[TreeNode]) -> List[int]:

# 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 preorderTraversal(self, root: Optional[TreeNode]) -> List[int]: