Package g0001_0100.s0098_validate_binary_search_tree

Class Solution

  • All Implemented Interfaces:
    
public final class Solution

    98 - Validate Binary Search Tree.

    Medium

    Given the root of a binary tree, determine if it is a valid binary search tree (BST).

    A valid BST is defined as follows:

    • The left subtree of a node contains only nodes with keys less than the node's key.

    • The right subtree of a node contains only nodes with keys greater than the node's key.

    • Both the left and right subtrees must also be binary search trees.

    Example 1:

    Input: root = 2,1,3

    Output: true

    Example 2:

    Input: root = 5,1,4,null,null,3,6

    Output: false

    Explanation: The root node's value is 5 but its right child's value is 4.

    Constraints:

    • The number of nodes in the tree is in the range <code>1, 10<sup>4</sup></code>.

    • <code>-2<sup>31</sup><= Node.val <= 2<sup>31</sup> - 1</code>

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description

    • Field Summary

      Fields 
      Modifier and Type Field Description

    • Constructor Summary

      Constructors 
      Constructor Description
      Solution()

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description

    • Method Summary

      Modifier and Type Method Description
      final Boolean isValidBST(TreeNode root)

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait