701 insert into a binary search tree

701. 二叉搜索树中的插入操作

go：

/**

 * Definition for a binary tree node.

 * type TreeNode struct {

 *     Val int

 *     Left *TreeNode

 *     Right *TreeNode

 * }
 */
func insertIntoBST(root *TreeNode, val int) *TreeNode {
    if root == nil {
        return &TreeNode{Val: val}
    }

    if root.Val > val {
        root.Left = insertIntoBST(root.Left, val)
    } else {
        root.Right = insertIntoBST(root.Right, val)
    }

    return root
}