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$ curl repovive.com/roadmaps/pattern-22/trees/validate-binary-search-tree-problem-statement

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$ curl repovive.com/roadmaps/pattern-22/trees/validate-binary-search-tree-problem-statement

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LeetCode 98 Validate Binary Search Tree - Problem Statement - Trees | Pattern 22: LeetCode Interview Patterns | Repovive

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Pattern 22: LeetCode Interview Patterns24 sections · 736 units32h total

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LeetCode 98 Validate Binary Search Tree - Problem Statement

The problem

Given the root of a binary tree, determine if it's a valid Binary Search Tree (BST).

A valid BST has these properties:

Every node in the left subtree has a value less than the node's value.
Every node in the right subtree has a value greater than the node's value.
Both subtrees are also valid BSTs.

This tree is valid:

  2
 / \
1   3

This tree is NOT valid (5 > 4 but 5 is in the right subtree of 4):

Constraints: $1 \le$ nodes $\le 10^4$ .