题目
Given the root of a Binary Search Tree (BST), return the minimum difference between the values of any two different nodes in the tree.
解题思路
对树进行中序遍历，因为中序遍历是有序的，所以遍历的时候和前一个遍历到的值作差，并更新结果
代码
# 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:
res = 100000
pre = -1
def minDiffInBST(self, root: Optional[TreeNode]) -> int:
def inorder(node):
if node.left:
inorder(node.left)
if self.pre >= 0:
self.res = min(self.res, node.val - self.pre)
self.pre = node.val
if node.right:
inorder(node.right)
inorder(root)
return self.res
