LeetCode 230. Kth Smallest Element in a BST in F#

URL https://leetcode.com/problems/kth-smallest-element-in-a-bst/ Code https://github.com/syohex/dotnet-study/blob/master/fsharp/leetcode/problems/0230/main.fsx type Tree = | Leaf | Node of int * Tree * Tree let kthSmallest (root: Tree) (k: i...