个人技术分享

题目：

题解：

class Solution:
    def recoverTree(self, root: Optional[TreeNode]) -> None:
        """
        Do not return anything, modify root in-place instead.
        """
        def inorder(node, lst):
            if not node:
                return
            inorder(node.left, lst)
            lst.append(node)
            inorder(node.right, lst)
        
        list = []
        inorder(root, list)
        n = len(list)
        a, b = None, None
        for i in range(n - 1):
            if list[i].val > list[i + 1].val:
                b = list[i + 1]
                if a is None:
                    a = list[i]
                elif a is not None:
                    break
        
        t = a.val
        a.val = b.val
        b.val = t