Problem link: Minimum Distance Between BST Nodes - LeetCode
Given the root of a Binary Search Tree (BST), return the minimum difference between the values of any two different nodes in the tree.
Example 1:
Input: root = [4,2,6,1,3] Output: 1
Example 2:
Input: root = [1,0,48,null,null,12,49] Output: 1
Constraints:
- The number of nodes in the tree is in the range
[2, 100]. 0 <= Node.val <= 105
Solution (C#):