0700. Search in a Binary Search Tree

700. Search in a Binary Search Tree#

题目 #

You are given the root of a binary search tree (BST) and an integer val.

Find the node in the BST that the node’s value equals val and return the subtree rooted with that node. If such a node does not exist, return null.

Example 1:

``````Input: root = [4,2,7,1,3], val = 2
Output: [2,1,3]
``````

Example 2:

``````Input: root = [4,2,7,1,3], val = 5
Output: []
``````

Constraints:

• The number of nodes in the tree is in the range [1, 5000].
• 1 <= Node.val <= 10000000
• root is a binary search tree.
• 1 <= val <= 10000000

解题思路 #

• 根据二叉搜索树的性质(根节点的值大于左子树所有节点的值，小于右子树所有节点的值),进行递归求解

代码 #

``````
package leetcode

import (
"github.com/halfrost/leetcode-go/structures"
)

// TreeNode define
type TreeNode = structures.TreeNode

/**
* 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
}
if root.Val == val {
return root
} else if root.Val < val {
return searchBST(root.Right, val)
} else {
return searchBST(root.Left, val)
}
}

``````

Apr 8, 2023
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