144. Binary Tree Preorder Traversal
144. Binary Tree Preorder Traversal
# Definition for a binary tree
Preorder Traversal
255. Verify Preorder Sequence in Binary Search Tree
255. Verify Preorder Sequence in Binary Search Tree
遞迴（超時）
589. N-ary Tree Preorder Traversal
589. N-ary Tree Preorder Traversal
"""
# Definition for a Node.
class
105. Construct Binary Tree from Preorder and Inorder Traversal
105. Construct Binary Tree from Preorder and Inorder Traversal
這一題的重點是，