From 723286ddf8580c91c9af35bb38aca5c8440c11da Mon Sep 17 00:00:00 2001
From: fw_qaq <82551626+fwqaaq@users.noreply.github.com>
Date: Sat, 17 Dec 2022 23:22:24 +0800
Subject: [PATCH] =?UTF-8?q?Update=200530.=E4=BA=8C=E5=8F=89=E6=90=9C?=
 =?UTF-8?q?=E7=B4=A2=E6=A0=91=E7=9A=84=E6=9C=80=E5=B0=8F=E7=BB=9D=E5=AF=B9?=
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---
 .../0530.二叉搜索树的最小绝对差.md | 28 ++++++++-----------
 1 file changed, 11 insertions(+), 17 deletions(-)

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 8c47b633..bc9645dc 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
@@ -547,31 +547,25 @@ impl Solution {
 递归中解决
 
 ```rust
-static mut PRE: Option<i32> = None;
-static mut MIN: i32 = i32::MAX;
-
 impl Solution {
     pub fn get_minimum_difference(root: Option<Rc<RefCell<TreeNode>>>) -> i32 {
-        unsafe {
-            PRE = None;
-            MIN = i32::MAX;
-            Self::inorder(root);
-            MIN
-        }
+        let mut pre = None;
+        let mut min = i32::MAX;
+        Self::inorder(root, &mut pre, &mut min);
+        min
     }
-    pub fn inorder(root: Option<Rc<RefCell<TreeNode>>>) {
+    pub fn inorder(root: Option<Rc<RefCell<TreeNode>>>, pre: &mut Option<i32>, min: &mut i32) {
         if root.is_none() {
             return;
         }
         let node = root.as_ref().unwrap().borrow();
-        Self::inorder(node.left.clone());
-        unsafe {
-            if let Some(pre) = PRE {
-                MIN = (node.val - pre).min(MIN).abs();
-            }
-            PRE = Some(node.val)
+        Self::inorder(node.left.clone(), pre, min);
+        if let Some(pre) = pre {
+            *min = (node.val - *pre).min(*min);
         }
-        Self::inorder(node.right.clone());
+        *pre = Some(node.val);
+
+        Self::inorder(node.right.clone(), pre, min);
     }
 }
 ```