package top100liked

// https://leetcode.cn/problems/convert-sorted-array-to-binary-search-tree/description/?envType=study-plan-v2&envId=top-100-liked

type TreeNode struct {
	Val   int
	Left  *TreeNode
	Right *TreeNode
}

func sortedArrayToBST(nums []int) *TreeNode {
	if len(nums) == 0 {
		return nil
	}
	if len(nums) == 1 {
		return &TreeNode{Val: nums[0]}
	}
	if len(nums) == 2 {
		return &TreeNode{Val: nums[1], Left: &TreeNode{Val: nums[0]}}
	}
	rootIdx := len(nums) / 2
	rootVal := nums[rootIdx]
	root := &TreeNode{Val: rootVal}
	root.Left = sortedArrayToBST(nums[:rootIdx])
	root.Right = sortedArrayToBST(nums[rootIdx+1:])
	return root
}