小黑宿舍楼边又有阳性了，纠结回不回家，不戴口罩又挨老黑说了的leetcode之旅:530. 二叉搜索树的最小绝对差

小黑代码

# 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:
    def getMinimumDifference(self, root: Optional[TreeNode]) -> int:
        self.pre_val = None
        self.cur_val = None
        self.min = float('inf')

        def dfs(node):
            if not node:
                return None
            dfs(node.left)
            self.pre_val = self.cur_val
            self.cur_val = node.val

            if self.pre_val != and abs(self.cur_val-self.pre_val) < self.min:
                
                self.min = abs(self.cur_val-self.pre_val)
            
            dfs(node.right)
        dfs(root)
        return self.min 
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小黑代码2

# 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:
    def getMinimumDifference(self, root: Optional[TreeNode]) -> int:
        
        q = []
        node = root
        pre_val = 0
        cur_val = -float('inf')
        min_ = float('inf')
        while q or node:
            while node:
                q.append(node)
                node = node.left
            top = q.pop()
            # 中序遍历
            pre_val = cur_val
            cur_val = top.val
            if abs(cur_val-pre_val) < min_:
                min_ = abs(cur_val-pre_val)
            node = top.right
        return min_
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小黑尝试mirrors法

# 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:
    def getMinimumDifference(self, root: Optional[TreeNode]) -> int:
        self.pre_val = -1
        self.cur_val = float('inf')
        self.min_ = float('inf')

        def select_min(val):
            self.pre_val = self.cur_val
            self.cur_val = val
            if abs(self.cur_val-self.pre_val) < self.min_:
                self.min_ = abs(self.cur_val-self.pre_val)

        curr = root
        # mirrors中序
        while curr:
            pre = curr.left
            if not pre:
                select_min(curr.val)
            else:
                while pre.right and pre.right != curr:
                    pre = pre.right
                if pre.right:
                    select_min(curr.val)
                    pre.right = None
                else:
                    pre.right = curr
                    curr = curr.left
                    continue
            curr = curr.right

        return self.min_              
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小黑生活

富河园的最后一顿饭，准备回学校

回到宿舍，配置pycharm解释器，把服务器弄崩了

早上发现隔壁楼阳了

在学校的恐惧生活

但还是要好好吃饭滴

和老黑们倒数的喝酒，喝的是阿黄的茅台

大家找工作都加油