https://leetcode.com/problems/minimum-absolute-difference-in-bst/

Author: harshitgindra

LeetCodeSolutions/BinarySearchTree/MinimumAbsoluteDifferenceInBst.cs

@@ -0,0 +1,49 @@
+namespace LeetCodeSolutions.BinarySearchTree;
+
+public class MinimumAbsoluteDifferenceInBst
+{
+    public int GetMinimumDifference(TreeNode root)
+    {
+        return InorderTraversal(root, int.MaxValue, null).minDiff;
+    }
+
+    private (int minDiff, TreeNode prev) InorderTraversal(TreeNode root, int minDiff, TreeNode prev)
+    {
+        if (root == null)
+        {
+            return (minDiff, prev);
+        }
+
+        (minDiff, prev) = InorderTraversal(root.left, minDiff, prev);
+
+        if (prev != null)
+        {
+            minDiff = Math.Min(minDiff, root.val - prev.val);
+        }
+
+        prev = root;
+
+        return InorderTraversal(root.right, minDiff, prev);
+    }
+
+    [Test(Description = "https://leetcode.com/problems/minimum-absolute-difference-in-bst/")]
+    [Category("Easy")]
+    [Category("LeetCode")]
+    [Category("Minimum absolute difference in BST")]
+    [TestCaseSource(nameof(Input))]
+    [Category("Binary Search Tree")]
+    [Category("TopInterview")]
+    public void Test1((int Output, int?[] Input) item)
+    {
+        var response = GetMinimumDifference(item.Input.ToTreeNode());
+        Assert.That(response, Is.EqualTo(item.Output));
+    }
+
+    public static IEnumerable<( int Output, int?[] Input)> Input =>
+        new List<(int Output, int?[] Input)>()
+        {
+            (9, [236, 104, 701, null, 227, null, 911]),
+            (1, [4, 2, 6, 1, 3]),
+            (1, [1, 0, 48, null, null, 12, 49]),
+        };
+}

LeetCodeSolutions/LeetCodeSolutions.csproj

@@ -14,7 +14,6 @@
     </ItemGroup>
  <ItemGroup>
    <Folder Include="Backtracking\" />
-   <Folder Include="BinarySearchTree\" />
    <Folder Include="GraphBfs\" />
    <Folder Include="Graph\" />
    <Folder Include="Heap\" />

README.md

@@ -139,7 +139,7 @@ The Top Interview 150 collection on Leetcode is a curated set of 150 interview q
 | 84                                           | Binary Tree Level Order Traversal                                                                         | Medium     |        |
 | 85                                           | Binary Tree Zigzag Level Order Traversal                                                                  | Medium     |        |
 | <br>        Binary Search Tree<br>           |                                                                                                           |            |        |
-| 86                                           | Minimum Absolute Difference in BST                                                                        | Easy       |        |
+| 86                                           | Minimum Absolute Difference in BST                                                                        | Easy       |    ✅    |
 | 87                                           | Kth Smallest Element in a BST                                                                             | Medium     |        |
 | 88                                           | Validate Binary Search Tree                                                                               | Medium     |        |
 | <br>        Graph General<br>                |                                                                                                           |            |        |