All Problems
Practice previous year questions from all companies and topics.
| Status | Problem Title | Difficulty | Company | Topic | Action |
|---|---|---|---|---|---|
Back to Microsoft Problems
mediumTrees
Validate Binary Search Tree
Description
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.
Constraints
- The number of nodes in the tree is in the range [1, 10^4].
- -2^31 <= Node.val <= 2^31 - 1
Code Editor Coming Soon!In Progress
We're building something amazing
Multi-language support (C++, Python, Java, JavaScript)
Real-time code execution with test cases
Syntax highlighting & auto-completion
Save your solutions automatically
Compare with optimal solutions
Development Progress65%
⚡ Expected launch: Q1 2026
💡 For now, practice solving on your local IDE and we'll notify you when the editor is ready!
Timer
0:00
Ready to start
Try to solve within 30-45 minutes. Good interview practice!
Problem Stats
Acceptance Rate68.4%
Total Solved1,245
Average Time25 mins
Your StatusNot Attempted