MathWorks HackerRank Assessment Questions and Prep Notes for 2026

MathWorks HackerRank Assessment Overview

The MathWorks HackerRank online assessment is commonly reported as a mix of short math reasoning questions and a longer technical section. In the experience summarized here, the assessment included a 15-minute math section, followed by a choice between an 85-minute coding section or a 70-minute MATLAB section. Exact formats can change by role, location, and hiring cycle, so always treat your official invitation as the source of truth.

This guide rewrites the reported assessment experience into a practical ExtraBrain prep article for candidates who want to understand the structure, rehearse the problem types, and review their reasoning responsibly. ExtraBrain is a free, local-first desktop AI interview assistant and meeting copilot for Mac that can help you practice explanations, review transcripts, and organize notes when AI assistance is allowed by the rules of your interview, employer, school, or assessment platform.

Reported Assessment Format

Sections

The reported MathWorks HackerRank assessment had three major components:

1. A multiple-choice math and logic section.
2. A coding section with two programming problems.
3. A MATLAB section that could be selected as an alternative to the coding section.

Timing and Points

Language Notes

In this reported experience, Python was not available for the coding section. The available coding languages were reported as C, C++, Java, and JavaScript. Because language support can vary, check the language list inside the live HackerRank environment before you commit to an approach.

Math Section Topics

The math section was described as short and mostly straightforward. The main challenge was not advanced math, but reading carefully under time pressure.

Reported question types included:

1. Probability of an event happening several times in a row.
2. Relative-position logic, such as deciding who comes before or after another person.
3. Matrix multiplication validity, including whether A × B or B × A is feasible.
4. Data interpretation from a table, followed by identifying which conclusions are correct.
5. Set-counting or inclusion-exclusion reasoning with people who like several categories such as A, B, C, D, and E.

For the final set-counting style question, write the conditions explicitly. If the question asks for people who like A and B but not D, do not stop at the A ∩ B count. Subtract the people inside that group who also satisfy D, and watch for overlaps with C or E if the prompt includes them.

Coding Question 1: Investable Periods

Problem Pattern

The first reported coding problem asked for contiguous subarrays where the maximum value equals a given max_price and the minimum value equals a given min_price. This is a common array-window pattern. A brute-force solution that checks every subarray and recomputes the minimum and maximum can be too slow for large inputs.

Reasoning Approach

Start by identifying what makes a subarray valid. A valid subarray must contain at least one occurrence of min_price, at least one occurrence of max_price, and no value that breaks the allowed range if the original problem constrains values between those bounds.

A strong approach is to scan from left to right and track the last important positions:

• The most recent index where the value was below min_price or above max_price.
• The most recent index where the value equaled min_price.
• The most recent index where the value equaled max_price.

At each index, the number of valid subarrays ending there depends on the earlier of the last min_price and last max_price positions, minus the last invalid boundary. If either required value has not appeared since the last invalid boundary, the contribution is zero.

Example Walkthrough

Suppose min_price = 2 and max_price = 5. If the scan has seen a 2 at index 3, a 5 at index 6, and the last out-of-range value was at index 1, then every start index from 2 through 3 can form a valid subarray ending at the current position. That is because the subarray must start after the invalid boundary and no later than the earlier required value.

Edge Cases to Practice

• min_price and max_price are equal.
• The array contains no min_price.
• The array contains no max_price.
• Invalid values split the array into independent segments.
• Many valid subarrays overlap.

Coding Question 2: Minimum Travel Cost

Problem Pattern

The second reported coding problem involved a city map where the goal was to calculate the minimum fuel cost to travel from one city to another. Each city had a different fuel price, and each road required a certain amount of fuel. A plain shortest-path algorithm is not enough if fuel can be purchased at multiple cities and the car has limited capacity.

Why Standard Dijkstra Needs State

Standard Dijkstra usually treats each city as a single node. For this problem family, reaching the same city with different remaining fuel can lead to different future costs. Arriving at city X with 0 fuel is not equivalent to arriving at city X with 10 fuel, especially if the next city has expensive fuel.

A more reliable model is to treat each state as:

(city, remaining_fuel)

From each state, you can consider two types of transitions:

1. Buy one more unit of fuel in the current city if the tank is not full.
2. Travel along an adjacent road if the remaining fuel is enough for that road.

The cost of buying fuel increases by the current city fuel price. The cost of traveling along a road can be modeled as zero additional money because the fuel was already purchased. Dijkstra can then search over the expanded state graph to find the cheapest way to reach the destination.

What to Watch For

• Fuel capacity limits the number of states per city.
• Road fuel requirements may exceed tank capacity, making some roads impossible.
• Buying all fuel at the current city is not always optimal.
• Sometimes buying just enough fuel to reach a cheaper city is best.
• The destination can be accepted when any remaining fuel state at that city has the minimum total cost.

Preparation Plan

A simple one-week plan is enough for many candidates if they already have basic data structure and algorithm fluency. The key is to practice under time limits and review mistakes immediately.

Practice Methods That Help

Practice the exact skill of reading a prompt, forming an approach, and turning it into clean code quickly. Do not only memorize solutions. MathWorks-style engineering assessments often reward careful modeling and clear edge-case handling.

Useful practice methods include:

• Solve problems with a visible timer.
• Alternate between easy, medium, and harder problems so you do not overfit to one difficulty level.
• Recode the same problem in your chosen assessment language after reading the editorial.
• Keep a short mistake log with the bug, the root cause, and the fix.
• Practice explaining your algorithm aloud in two minutes.

ExtraBrain can be useful before the assessment for mock interviews, answer outlines, and post-practice review. Use it only in settings where AI assistance, transcription, screenshots, and notes are permitted.

Solving Strategy for Coding Problems

Read Before Coding

Read the problem statement twice before writing code. Look for input limits, constraints, examples, and unusual wording. If the input size is large, assume a brute-force solution may fail even if it is easy to write.

Identify the State

Many online assessment problems become easier once you identify the correct state. For the investable-periods problem, the state can be the latest positions of invalid values and required boundary values. For the travel-cost problem, the state can be the current city plus the remaining fuel.

Choose the Data Structure

Use the data structure that matches the state transitions. For sliding-window counting, indices and running variables may be enough. For minimum-cost graph search, a priority queue is usually the right tool.

Test Small Cases First

Before submitting, test cases that are small enough to verify manually. For array questions, include empty-like boundaries, repeated values, and invalid split points. For graph questions, include unreachable destinations, roads that exceed capacity, and paths that require refueling at a cheaper city.

Math and Logic Strategy

Probability

For repeated independent events, multiply the probability for each occurrence. If the probability of event A is p, the probability that it occurs five times in a row is p^5, assuming each occurrence is independent.

Relative Position Questions

Translate each sentence into an ordering constraint. Then draw a line or write a small list of possible positions. Avoid keeping all relationships in your head.

Matrix Multiplication

Matrix multiplication A × B is valid when the number of columns in A equals the number of rows in B. If A is m × n and B is p × q, then A × B is valid only when n = p. The result has shape m × q.

Data Interpretation

Read table labels before reading answer choices. Many wrong answers are close to correct but use the wrong row, column, denominator, or time period.

Inclusion-Exclusion

For overlap questions, write each group as a set. Then decide whether the prompt asks for union, intersection, exactly one category, at least one category, or a category with exclusions.

Responsible Use of AI During Preparation

ExtraBrain is designed for interview preparation, live context support, and review workflows, but responsible use matters. You should follow every rule from the employer, recruiter, assessment platform, school, and workplace. If an assessment forbids AI assistance, use AI only before or after the assessment for practice and review.

A responsible prep workflow looks like this:

1. Practice a problem on your own first.
2. Use ExtraBrain to summarize your reasoning or identify weak spots after the attempt.
3. Ask for alternative explanations if you did not understand the editorial.
4. Re-solve the problem without looking at generated help.
5. Record the pattern in your own words.

This builds skill instead of dependence. It also keeps your process aligned with honest assessment expectations.

FAQ

What is the MathWorks HackerRank assessment like?

In this reported experience, it included a 15-minute math section and then either an 85-minute coding section or a 70-minute MATLAB section. The exact format may vary, so check your official instructions.

What coding questions were reported?

Two patterns were reported. One involved counting contiguous subarrays where the minimum and maximum matched target prices. The other involved finding minimum fuel cost across a graph of cities with different fuel prices.

Is Python allowed in the MathWorks HackerRank assessment?

In this reported experience, Python was not available for the coding section. The reported languages were C, C++, Java, and JavaScript. Always verify the available languages in your own assessment environment.

Can I switch between the coding and MATLAB sections after starting?

The reported experience said no. Candidates had to choose one section before starting and could not switch after beginning.

Are partial solutions graded?

Yes, partial credit is commonly possible when some test cases pass. That means a simple correct baseline can be better than an unfinished complex solution. After the baseline passes samples, improve performance and edge-case coverage.

How can ExtraBrain help me prepare?

ExtraBrain can help you run mock interviews, explain coding approaches aloud, review session transcripts, capture screen-aware context, and turn mistakes into a focused study plan. The core Mac app is free, supports bring-your-own AI providers, and can use local-first options where installed and compatible. Use it only where AI assistance and recording-style features are allowed.

See Also

• ExtraBrain for local-first AI interview preparation and meeting support.
• Responsible use guidance for deciding when AI assistance is appropriate.
• ExtraBrain privacy information for understanding local and external-provider data flow.
• ExtraBrain help center for setup, providers, transcription, and session review.