84 lines
1.9 KiB
Java
84 lines
1.9 KiB
Java
//给定一个二叉搜索树 root 和一个目标结果 k，如果 BST 中存在两个元素且它们的和等于给定的目标结果，则返回 true。
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//
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//
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//
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// 示例 1：
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//
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//
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//输入: root = [5,3,6,2,4,null,7], k = 9
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//输出: true
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//
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//
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// 示例 2：
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//
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//
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//输入: root = [5,3,6,2,4,null,7], k = 28
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//输出: false
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//
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//
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//
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//
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// 提示:
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//
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//
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// 二叉树的节点个数的范围是 [1, 10⁴].
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// -10⁴ <= Node.val <= 10⁴
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// root 为二叉搜索树
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// -10⁵ <= k <= 10⁵
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//
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// Related Topics 树 深度优先搜索 广度优先搜索 二叉搜索树 哈希表 双指针 二叉树 👍 373 👎 0
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package leetcode.editor.cn;
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import com.code.leet.entiy.TreeNode;
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import java.util.ArrayList;
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import java.util.List;
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//653:两数之和 IV - 输入 BST
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public class TwoSumIvInputIsABst {
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public static void main(String[] args) {
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Solution solution = new TwoSumIvInputIsABst().new Solution();
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}
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//leetcode submit region begin(Prohibit modification and deletion)
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/**
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* Definition for a binary tree node.
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* public class TreeNode {
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* int val;
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* TreeNode left;
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* TreeNode right;
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* TreeNode() {}
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* TreeNode(int val) { this.val = val; }
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* TreeNode(int val, TreeNode left, TreeNode right) {
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* this.val = val;
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* this.left = left;
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* this.right = right;
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* }
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* }
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*/
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class Solution {
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public boolean findTarget(TreeNode root, int k) {
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if (root == null) {
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return false;
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}
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if (list.contains(k - root.val)) {
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return true;
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}
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list.add(root.val);
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if (findTarget(root.left, k)) {
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return true;
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}
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if (findTarget(root.right, k)) {
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return true;
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}
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return false;
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}
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List<Integer> list = new ArrayList<>();
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}
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//leetcode submit region end(Prohibit modification and deletion)
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} |