PROGRAMMING SKILLS

Coding binary trees test for hiring

See how candidates turn a binary tree problem into working code.

35 minutes
1 task
Intermediate
Coding tasks
Questions in English
Desktop only

Use this test free See the question formats

The short answer

Coding: Binary Trees is an intermediate programming skills test for hiring software engineers, backend and full-stack developers, and other roles where tree structures matter. In one code-editor task, candidates write a working solution to a traversal, binary search tree check, or path calculation. The score reflects hidden test cases passed.

What it measures

Writing correct code that builds, walks and reasons about binary trees.

Binary tree problem solving

Candidates build, walk, and reason about binary trees to solve problems such as traversals, search tree checks, and path calculations.

Question formats

Coding tasks

The candidate: Writes or fixes code in an editor and runs it against examples.

You see: Working code, checked against hidden test cases, not just knowledge of syntax.

1 task in 35 minutes.

Roles this test fits

Software engineers, backend and full-stack developers, game developers, data engineers, data scientists who write production code, and other roles where tree structures matter for storing, searching and processing data.

What this coding task can show

Working logic, not just claims
Candidates write a solution to a binary tree problem, and the score reflects how many hidden test cases it passes.
Three kinds of tree problem
The task drawn may be a traversal, a binary search tree check or a path calculation, so each one asks the candidate to handle real tree structure in working code.
Fair limits for tree solutions
Limits are set so a clear linear-time solution to the tree problem passes in every supported language, so a candidate is not held back by writing in Python rather than C++.

What you get for each candidate

Example report (fictional data)Coding: Binary Trees

63%Percentile 29. Benchmark: HireValid candidates, n = 903

Binary tree problem solving63%

Integrity ScoreHigh confidence

Stayed on the test tab throughout
No pasted answers
Answered at a steady pace

Scores, profiles and integrity signals are evidence for you to review alongside an interview, never an automatic decision.

Use this test free

Integrity signals for review

Each candidate receives a different question drawn from a large pool. Code runs against hidden test cases on HireValid’s servers; the cases and solutions do not reach the browser, and pastes into the editor are recorded. The server runs the 35-minute timer, so reloading restores the same question with only the time left. The question cannot be copied or selected, and blocked copy attempts appear in the timeline. HireValid can summarize signals such as time away from the test tab, pastes, and answers faster than a question can be read in an Integrity Score with an evidence timeline. Review those signals yourself; they do not decide on their own. With candidate consent, you can add webcam photos at random moments.

How we prevent AI cheating · Integrity signals

Use the score as one piece of evidence

Review the score as evidence from one binary tree task, not as a verdict. A single task gives a narrow sample, and scores can vary with the problem drawn. Pair it with a work sample where the candidate builds, walks, or reasons through a tree structure, then use a structured interview to explore their choices. For broader context on software hiring, compare it with the Algorithms for Software Engineering test, Object Oriented Programming test, or Clean Code test.

Structured interview questions

How would you approach checking whether a binary tree meets a given condition?
Listen for a clear plan for visiting nodes, checking the required condition, and considering edge cases before coding.
Tell me about a time you had to reason through a tree-shaped data problem in production code. How did you decide on an approach?
Look for a concrete account of the data, the candidate’s reasoning, and how they checked that their solution handled the relevant cases.
If your tree traversal passed the examples but failed a hidden case, how would you investigate and revise it?
Listen for a systematic way to trace the traversal, test boundary cases, and explain the change rather than guessing.

Understand scoring and benchmarks

Fairness and accommodations

Every task states its input format, its limits and the expected output in plain words with worked examples, so no particular textbook or platform habit is needed. Candidates choose from six common languages, tasks avoid trivia and domain knowledge, scenarios use neutral settings with names from many backgrounds, and limits are set so a clear linear-time solution passes in every supported language.

You can give any candidate extra time as an accommodation. Results are evidence for a person to review, never an automatic decision.

Provisional: a single task gives a narrow sample of skill, so scores can vary with the problem drawn. Reliability is reported once 200 candidates have completed it.

Read our fairness approach

Test details

One coding task on binary trees, solved in a code editor within 35 minutes. The candidate writes a working solution to a problem such as a traversal, a binary search tree check or a path calculation, and the score reflects how many hidden test cases the solution passes. Candidates may write in Python, JavaScript, Java, C#, C++ or Go.

Questions are in English.
Aids allowed: Scratch paper.
1 practice task, 10 minutes, before the timed test.
Taken on a desktop or laptop computer.

Python, JavaScript, Java, C#, C++, Go are trademarks of their owners. HireValid is not affiliated with or endorsed by them.

Frequently asked questions

Who should take the Coding: Binary Trees test?+

It is an intermediate test for software engineers, backend and full-stack developers, game developers, and other roles where tree structures matter for storing, searching, or processing data. It may also fit data engineers and data scientists who write production code. Choose it when binary tree problem solving is relevant to the role.

How does the Coding: Binary Trees test keep the task clear?+

Each task states its input format, limits and expected output in plain words, with worked examples. Its binary tree problem does not require a particular textbook or platform habit, tasks avoid trivia and domain knowledge, and scenarios use neutral settings with names from many backgrounds.

Can candidates use scratch paper for the Coding: Binary Trees test?+

Yes. Scratch paper is allowed, and the test is desktop-only. Candidates solve the task in a code editor and can choose from six supported languages. That can help you assess how they build, traverse, or reason about a binary tree while reviewing code in a language they know.

What does the Coding: Binary Trees practice set include?+

The practice set has one question and takes 10 minutes. It gives candidates a chance to get familiar with the test format before the assessed task. The test itself is one coding task, with a 35-minute time limit.