Merge branch 'youngyangyang04:master' into master

problems/0530.二叉搜索树的最小绝对差.md

@@ -221,8 +221,27 @@ 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
+        
+        
+class Solution: # 双指针法，不用数组 (同Carl写法) - 更快
+    def getMinimumDifference(self, root: Optional[TreeNode]) -> int:
+        global pre,minval
+        pre = None
+        minval = 10**5
+        self.traversal(root)
+        return minval
+
+    def traversal(self,root):
+        global pre,minval
+        if not root: return None
+        self.traversal(root.left)
+        if pre and root.val-pre.val<minval: 
+            minval = root.val-pre.val
+        pre = root
+        self.traversal(root.right)            
 ```
 
+
 迭代法-中序遍历
 ```python 
 class Solution: