LeetCode 653. [Java]Two Sum IV - Input is a BST
原题链接
简单
作者:
tt2767
,
2022-04-20 16:51:33
,
所有人可见
,
阅读 292
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode() {}
* TreeNode(int val) { this.val = val; }
* TreeNode(int val, TreeNode left, TreeNode right) {
* this.val = val;
* this.left = left;
* this.right = right;
* }
* }
*/
/**
1. 求两个元素的总和, 沿途记录出现过的值, 并找下target - val的查值是否出现过
*/
class Solution {
public boolean findTarget(TreeNode root, int k) {
return findTarget(root, k, new HashSet<Integer>());
}
public boolean findTarget(TreeNode root, int k, Set<Integer> set) {
if (root == null) return false;
if (set.contains(k - root.val)) return true;
set.add(root.val);
return findTarget(root.left, k, set) || findTarget(root.right, k, set);
}
}