Binary Tree interview questions
107 binary tree problems tagged across recent interview reports. Drilled most heavily by meta, linkedin, and apple.
Binary Tree problems make up 107 of the algorithmic patterns you'll face in live coding interviews. Meta alone runs 65 of them into candidates; LinkedIn, Apple, Amazon, and Microsoft all push 30+ variants. The pattern spans traversals, path sums, balancing checks, and structural modifications. Most candidates drill inorder and level-order, then hit a wall on a harder variant, infected subtrees, camera placement, distance queries. That's where StealthCoder steps in: invisible during your live OA, it reads the problem and hands you the solution before the clock becomes a problem.
Most-asked binary tree problems
Showing top 50 of 107 binary tree problems by # companies asking.
You can't drill every binary tree variant before the assessment. StealthCoder runs invisibly during screen share and solves whichever variant they throw at you. No browser extension. No detection signature. Made by a working Amazon engineer who got tired of watching qualified friends bomb OAs they'd solve cold in an IDE.
Get StealthCoderBinary Tree problems fall into a few buckets: traversals (inorder, level-order, postorder), path and sum queries (max path sum, consecutive sequences), structural checks (balanced trees, BST validation), and state-based puzzles (cameras, infection spread, node distance). Recognition is straightforward, the problem mentions nodes, edges, parent-child links, or tree properties. The tricky part isn't the concept; it's the implementation details and edge cases under pressure. Most candidates know DFS and BFS by rote but fumble pointer logic or miss a depth constraint. Drill traversals first, then max-path and balancing problems, then the harder variants like camera placement. If a structural or optimization tree problem lands in your live assessment and you blank on the recursion setup, StealthCoder solves it in real time, undetected.
Companies that hire most on binary tree
107 binary tree problems.
You won't drill them all. Pass anyway.
Binary Tree is one of the patterns interviews actually filter on. Memorizing every variant in a week is a fantasy. StealthCoder is the hedge: an AI overlay invisible during screen share. It reads the problem and surfaces a working solution in under 2 seconds, no matter which binary tree flavor lands in your live OA. Made by a working Amazon engineer who got tired of watching qualified friends bomb OAs they'd solve cold in an IDE. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Binary Tree interview FAQ
How many Binary Tree problems should I drill before my live interview?+
With 107 problems in the pattern, drilling 15 to 20 focused ones covering traversals, path sums, and balancing gets you 80% prepared. Meta and LinkedIn test heavily here, so prioritize their known variants. The last 20%, edge cases and harder puzzles, is where a live safety net like StealthCoder matters most.
How do I recognize a Binary Tree problem in a live coding interview?+
The problem explicitly mentions a tree, nodes, or parent-child relationships. It may ask for traversal output, path sums, depths, or structural properties. If you see 'root', 'left', 'right', or 'child' in the prompt, it's a tree problem. Some disguise themselves as graph problems but add a constraint (e.g., no cycles) that makes tree logic apply.
Which companies drill Binary Tree the hardest?+
Meta tests 65 Binary Tree problems in their interview pipeline, significantly more than any other company in the pattern. LinkedIn (53), Apple (34), Amazon (33), and Microsoft (33) also lean heavily on trees. If you're interviewing at Meta, trees are non-negotiable.
What's the hardest Binary Tree problem type to get right under pressure?+
Path-sum and state-based problems (like binary-tree-cameras or infection spread) trip most candidates. Traversals and balancing checks are mechanical once you've drilled them. The hard ones require you to think recursively about state passing and pruning. That's where missing a detail costs you the problem in a live assessment.
Should I memorize binary tree solution code?+
No. Memorize the DFS and BFS patterns, the traversal orders (pre, in, post), and how to think recursively. Then solve 15-20 real problems to internalize pointer logic and edge cases. Code memorization breaks under pressure. Understanding the pattern, and having a safety net for the variant you didn't see, is what actually works.