algorithm/leetcode-master
1
0
Fork 0
mirror of https://github.com/youngyangyang04/leetcode-master.git synced 2025-07-09 11:34:46 +08:00
Code Issues Packages Projects Releases Wiki Activity

Merge pull request #828 from casnz1601/patch-7

Browse Source 
Update 0669.修剪二叉搜索树.md
This commit is contained in:
程序员Carl
2021-10-11 09:27:54 +08:00
committed by GitHub
parent a080032a8f 0d99a3975e
commit e44707696c
1 changed files with 28 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
problems/0669.修剪二叉搜索树.md
View File

@ -265,18 +265,35 @@ class Solution {
``` ```
## Python ## Python
**递归**
```python3 ```python3
# 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: class Solution:
def trimBST(self, root: TreeNode, low: int, high: int) -> TreeNode: def trimBST(self, root: TreeNode, low: int, high: int) -> TreeNode:
if not root: return root '''
确认递归函数参数以及返回值：返回更新后剪枝后的当前root节点
'''
# Base Case
if not root: return None
# 单层递归逻辑
if root.val < low: if root.val < low:
return self.trimBST(root.right,low,high) // 寻找符合区间[low, high]的节点 # 若当前root节点小于左界：只考虑其右子树，用于替代更新后的其本身，抛弃其左子树整体
if root.val > high: return self.trimBST(root.right, low, high)
return self.trimBST(root.left,low,high) // 寻找符合区间[low, high]的节点
root.left = self.trimBST(root.left,low,high) // root->left接入符合条件的左孩子 if high < root.val:
root.right = self.trimBST(root.right,low,high) // root->right接入符合条件的右孩子 # 若当前root节点大于右界：只考虑其左子树，用于替代更新后的其本身，抛弃其右子树整体
return self.trimBST(root.left, low, high)
if low <= root.val <= high:
root.left = self.trimBST(root.left, low, high)
root.right = self.trimBST(root.right, low, high)
# 返回更新后的剪枝过的当前节点root
return root return root
``` ```