class Solution:
    def minDiffInBST(self, root: TreeNode) -> int:
        self.preVal = None
        self.res = float('inf')
        self.dfs(root)
        return self.res
    def dfs(self,root):
        if not root: return
        self.dfs(root.left)
        if self.preVal != None:
            self.res = min(self.res,root.val-self.preVal)
        self.preVal = root.val
        self.dfs(root.right)

树 简单 每日一题

https://leetcode-cn.com/problems/minimum-distance-between-bst-nodes/

与 0530.二叉搜索树的最小绝对差.md 相同