-
Notifications
You must be signed in to change notification settings - Fork 0
/
problem_105.py
30 lines (25 loc) · 947 Bytes
/
problem_105.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
# coding:utf-8
# Created by: Jiaming
# Created at: 2020-03-20
# 根据一棵树的前序遍历与中序遍历构造二叉树。
from typing import List
from utils import TreeNode, levelOrder
class Solution:
def buildTree(self, preorder: List[int], inorder: List[int]) -> TreeNode:
if not preorder:
return None
if len(preorder) == 1:
return TreeNode(preorder[0])
root = TreeNode(preorder[0])
index = inorder.index(root.val)
left_inorder = inorder[0:index]
right_inorder = inorder[index + 1:]
left_preorder = preorder[1:index + 1]
right_preorder = preorder[index + 1:]
root.left = self.buildTree(left_preorder, left_inorder)
root.right = self.buildTree(right_preorder, right_inorder)
return root
if __name__ == "__main__":
s = Solution()
res = s.buildTree([3, 9, 20, 15, 7], [9, 3, 15, 20, 7])
print(levelOrder(res))