653. Both Sum Iv-input is a BST

Source: Internet
Author: User

Given a Binary Search Tree and a target number, return True if there exist the elements in the BST such that their sum is Equal to the given target.

Example 1:

Input:     5   /   3   6/\   2   4   7Target = 9output:true

Example 2:

Input:     5   /   3   6/\   2   4   7Target = 28output:false
//time:o (n), Space:o (n)//beginning to think of BST with two points, and later found that the problem and two-fork search tree does not matter, is to traverse a normal two-fork tree  Public BooleanFindtarget (TreeNode root,intk) {if(Root = =NULL) {            return false; } HashSet<Integer> set =NewHashset<integer>(); returnDfs (root, k, set); }        Private BooleanDFS (TreeNode root,intK, hashset<integer>set) {        if(Root = =NULL) {            return false; }                if(Set.contains (K-root.val)) {return true;        } set.add (Root.val); returnDFS (Root.left, K, set) | |Dfs (Root.right, k, set); }

653. Both Sum Iv-input is a BST

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.