Given the root of a binary search tree and an integer k, return the kth smallest value (1-indexed) in the tree.
A binary search tree satisfies the following constraints:
Constraints:
Examples:
// Example 1:
// 2
// / \
// 1 3
const root1 = createTree([2, 1, 3]);
console.log(kthSmallest(root1, 1));
// Output: 1
// Example 2:
// 4
// / \
// 3 5
// /
// 2
const root2 = createTree([4, 3, 5, 2]);
console.log(kthSmallest(root2, 4));
// Output: 5