lowest-common-ancestor-of-a-binary-search-tree.go

package problem0235

import "github.com/aQuaYi/LeetCode-in-Go/kit"

// TreeNode is pre-defined..
type TreeNode = kit.TreeNode

func lowestCommonAncestor(root, p, q *TreeNode) *TreeNode {
	return helper(root, p.Val, q.Val)
}

func helper(root *TreeNode, p, q int) *TreeNode {
	r := root.Val
	if p < r && q < r {
		return helper(root.Left, p, q)
	} else if r < p && r < q {
		return helper(root.Right, p, q)
	}
	return root
}