LeetCode 98. 数据结构->验证二叉搜索树(递归判断节点的数值范围
原题链接
中等
作者:
JustDoIt11
,
2023-10-31 12:30:19
,
所有人可见
,
阅读 47
/**
* 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;
* }
* }
*/
class Solution {
public boolean isValidBST(TreeNode root) {
return dfs(root, Long.MIN_VALUE, Long.MAX_VALUE);
}
public boolean dfs(TreeNode t, long low, long hig) {
if (t == null) return true;
if (t.val <= low || t.val >= hig) return false;
return dfs(t.left, low, t.val) && dfs(t.right, t.val, hig);
}
}