添加 98验证二叉搜索树Java简洁代码

This commit is contained in:
zhenzi
2021-05-15 11:10:47 +08:00
parent 060f1eadb3
commit 8dedebcc8d

View File

@ -304,6 +304,35 @@ class Solution {
return true; return true;
} }
} }
// 简洁实现·递归解法
class Solution {
public boolean isValidBST(TreeNode root) {
return validBST(Long.MIN_VALUE, Long.MAX_VALUE, root);
}
boolean validBST(long lower, long upper, TreeNode root) {
if (root == null) return true;
if (root.val <= lower || root.val >= upper) return false;
return validBST(lower, root.val, root.left) && validBST(root.val, upper, root.right);
}
}
// 简洁实现·中序遍历
class Solution {
private long prev = Long.MIN_VALUE;
public boolean isValidBST(TreeNode root) {
if (root == null) {
return true;
}
if (!isValidBST(root.left)) {
return false;
}
if (root.val <= prev) { // 不满足二叉搜索树条件
return false;
}
prev = root.val;
return isValidBST(root.right);
}
}
``` ```
Python Python