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Update 0538.把二叉搜索树转换为累加树.md
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@ -200,8 +200,30 @@ class Solution {
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```
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## Python
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**递归**
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递归法(版本一)
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```python
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# Definition for a binary tree node.
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# class TreeNode:
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# def __init__(self, val=0, left=None, right=None):
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# self.val = val
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# self.left = left
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# self.right = right
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class Solution:
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def convertBST(self, root: TreeNode) -> TreeNode:
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self.pre = 0 # 记录前一个节点的数值
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self.traversal(root)
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return root
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def traversal(self, cur):
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if cur is None:
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return
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self.traversal(cur.right)
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cur.val += self.pre
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self.pre = cur.val
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self.traversal(cur.left)
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```
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递归法(版本二)
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```python
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# Definition for a binary tree node.
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# class TreeNode:
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@ -234,7 +256,32 @@ class Solution:
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return root
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```
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**迭代**
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迭代法(版本一)
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```python
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class Solution:
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def __init__(self):
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self.pre = 0 # 记录前一个节点的数值
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def traversal(self, root):
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stack = []
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cur = root
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while cur or stack:
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if cur:
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stack.append(cur)
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cur = cur.right # 右
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else:
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cur = stack.pop() # 中
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cur.val += self.pre
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self.pre = cur.val
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cur = cur.left # 左
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def convertBST(self, root):
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self.pre = 0
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self.traversal(root)
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return root
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```
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迭代法(版本二)
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```python
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class Solution:
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def convertBST(self, root: Optional[TreeNode]) -> Optional[TreeNode]:
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