#106

Construct Binary Tree from Inorder and Postorder Traversal

pupil · 580 · lc medium +29 · verified · 68.1% accepted · 8,671 likes · top 75%

Description

You are given two integer arrays: inorder, the inorder traversal of a binary tree, and postorder, its postorder traversal. Use both sequences to rebuild and return the binary tree.

Example 1:

Input: inorder = [9,3,15,20,7], postorder = [9,15,7,20,3]

Output: [3,9,20,null,null,15,7]

Example 2:

Input: inorder = [-1], postorder = [-1]

Output: [-1]

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 buildTree(self, inorder: List[int], postorder: List[int]) -> Optional[TreeNode]:

# 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 buildTree(self, inorder: List[int], postorder: List[int]) -> Optional[TreeNode]: