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Merge pull request youngyangyang04#830 from casnz1601/patch-9

Update 0538.把二叉搜索树转换为累加树.md

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- 0538.把二叉搜索树转换为累加树.md

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`‎problems/0538.把二叉搜索树转换为累加树.md`

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Original file line number	Diff line number	Diff line change
`@@ -196,20 +196,40 @@ class Solution {`
`196`	`196`	```
`197`	`197`
`198`	`198`	`## Python`
`199`		`-`
`200`		`-递归法`
`201`		-```python
	`199`	`+递归`
	`200`	`+`
	`201`	+```python3
	`202`	`+# Definition for a binary tree node.`
	`203`	`+# class TreeNode:`
	`204`	`+# def __init__(self, val=0, left=None, right=None):`
	`205`	`+# self.val = val`
	`206`	`+# self.left = left`
	`207`	`+# self.right = right`
`202`	`208`	`class Solution:`
`203`		`- def convertBST(self, root: TreeNode) -> TreeNode:`
`204`		`- defbuildalist(root):`
`205`		`-ifnot root: returnNone`
`206`		`- buildalist(root.right) #右中左遍历`
`207`		`- root.val +=self.pre`
`208`		`- self.pre = root.val`
`209`		`- buildalist(root.left)`
`210`		`- self.pre =0#记录前一个节点的数值`
`211`		`- buildalist(root)`
	`209`	`+ def __init__(self):`
	`210`	`+ self.pre = TreeNode()`
	`211`	`+`
	`212`	`+ defconvertBST(self, root: Optional[TreeNode]) -> Optional[TreeNode]:`
	`213`	`+ '''`
	`214`	`+ 倒序累加替换:`
	`215`	`+ [2, 5, 13] -> [[2]+[1]+[0], [2]+[1], [2]] -> [20, 18, 13]`
	`216`	`+ '''`
	`217`	`+ self.traversal(root)`
`212`	`218`	`return root`
	`219`	`+`
	`220`	`+ def traversal(self, root: TreeNode) -> None:`
	`221`	`+ # 因为要遍历整棵树,所以递归函数不需要返回值`
	`222`	`+ # Base Case`
	`223`	`+ if not root:`
	`224`	`+ return None`
	`225`	`+ # 单层递归逻辑:中序遍历的反译 - 右中左`
	`226`	`+ self.traversal(root.right) # 右`
	`227`	`+`
	`228`	`+ # 中节点:用当前root的值加上pre的值`
	`229`	`+ root.val += self.pre.val # 中`
	`230`	`+ self.pre = root`
	`231`	`+`
	`232`	`+ self.traversal(root.left) # 左`
`213`	`233`	```
`214`	`234`
`215`	`235`	`## Go`

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