diff --git a/problems/0106.从中序与后序遍历序列构造二叉树.md b/problems/0106.从中序与后序遍历序列构造二叉树.md index 4cc2a88a..cfd22288 100644 --- a/problems/0106.从中序与后序遍历序列构造二叉树.md +++ b/problems/0106.从中序与后序遍历序列构造二叉树.md @@ -618,8 +618,42 @@ class Solution { ``` Python: - - +105.从前序与中序遍历序列构造二叉树 +```python +# 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 +//递归法 +class Solution: + def buildTree(self, preorder: List[int], inorder: List[int]) -> TreeNode: + if not preorder: return None //特殊情况 + root = TreeNode(preorder[0]) //新建父节点 + p=inorder.index(preorder[0]) //找到父节点在中序遍历的位置(因为没有重复的元素,才可以这样找) + root.left = self.buildTree(preorder[1:p+1],inorder[:p]) //注意左节点时分割中序数组和前续数组的开闭环 + root.right = self.buildTree(preorder[p+1:],inorder[p+1:]) //分割中序数组和前续数组 + return root +``` +106.从中序与后序遍历序列构造二叉树 +```python +# 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 +//递归法 +class Solution: + def buildTree(self, inorder: List[int], postorder: List[int]) -> TreeNode: + if not postorder: return None //特殊情况 + root = TreeNode(postorder[-1]) //新建父节点 + p=inorder.index(postorder[-1]) //找到父节点在中序遍历的位置*因为没有重复的元素,才可以这样找 + root.left = self.buildTree(inorder[:p],postorder[:p]) //分割中序数组和后续数组 + root.right = self.buildTree(inorder[p+1:],postorder[p:-1]) //注意右节点时分割中序数组和后续数组的开闭环 + return root +``` Go: @@ -643,4 +677,4 @@ var buildTree = function(inorder, postorder) { * 作者微信:[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw) * B站视频:[代码随想录](https://space.bilibili.com/525438321) * 知识星球:[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ) -
\ No newline at end of file +