From 3ab914332ebfe60020061d2bc4bd9102687f4841 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E8=97=A4=E9=9C=B2?= <080301087@163.com>
Date: Thu, 8 Jul 2021 17:02:29 +0800
Subject: [PATCH] =?UTF-8?q?Update=200530.=E4=BA=8C=E5=8F=89=E6=90=9C?=
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---
 .../0530.二叉搜索树的最小绝对差.md | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/problems/0530.二叉搜索树的最小绝对差.md b/problems/0530.二叉搜索树的最小绝对差.md
index 47b2b434..bf646443 100644
--- a/problems/0530.二叉搜索树的最小绝对差.md
+++ b/problems/0530.二叉搜索树的最小绝对差.md
@@ -222,6 +222,26 @@ class Solution:
         for i in range(len(res)-1):  // 统计有序数组的最小差值
             r = min(abs(res[i]-res[i+1]),r)
         return r
+        
+# 迭代法-中序遍历
+class Solution:
+    def getMinimumDifference(self, root: TreeNode) -> int:
+        stack = []
+        cur = root
+        pre = None
+        result = float('inf')
+        while cur or stack:
+            if cur: # 指针来访问节点，访问到最底层
+                stack.append(cur)
+                cur = cur.left
+            else: # 逐一处理节点
+                cur = stack.pop()
+                if pre: # 当前节点和前节点的值的差值
+                    result = min(result, cur.val - pre.val)
+                pre = cur
+                cur = cur.right
+        return result
+        
 ```
 Go：
 > 中序遍历，然后计算最小差值