700 search in a binary search tree

700. 二叉搜索树中的搜索

go：

递归

/**

 * Definition for a binary tree node.

 * type TreeNode struct {

 *     Val int

 *     Left *TreeNode

 *     Right *TreeNode

 * }
 */
func searchBST(root *TreeNode, val int) *TreeNode {
    if root == nil {
        return nil
    }

    switch {
        case root.Val == val:
            return root
        case root.Val > val :
            return searchBST(root.Left, val)
        default: 
            return searchBST(root.Right, val)
    }
}

迭代

/**

 * Definition for a binary tree node.

 * type TreeNode struct {

 *     Val int

 *     Left *TreeNode

 *     Right *TreeNode

 * }
 */
func searchBST(root *TreeNode, val int) *TreeNode {
    for root != nil {
        if root.Val == val {
            return root
        } else if root.Val > val {
            root = root.Left
        } else {
            root = root.Right
        }
    }

    return nil
}