530. Minimum Absolute Difference in BST

Given a binary search tree with non-negative values, find the minimum absolute difference between values of any two nodes.

Example:

Input:

   1
         3
    /
   2

Output:
1

Explanation:
The minimum absolute difference is 1, which is the difference between 2 and 1 (or between 2 and 3).

Note:

• There are at least two nodes in this BST.
• This question is the same as 783: https://leetcode.com/problems/minimum-distance-between-bst-nodes/