Optiver Interview Questions — Page 4

Optiver·Software Engineer·Technical Phone Screen

May 2026

Optiver software engineer interview with a coding problem that looked straightforward until I actually had to implement it from scratch. No date libraries allowed, which is where things got uncomfortable fast.

Given two dates as (year, month, day) tuples where the first is guaranteed to be earlier, compute the number of days between them without using any built-in date or time library. You are given a helper function DaysInMonth(month, year) that returns the number of days in a given month.

“I thought I had this immediately and started coding before really thinking it through.”

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Optiver·Software Engineer·Onsite - System Design / Architecture

May 2026

System design round at Optiver for a software engineering role, focused entirely on building a pub/sub notification service from scratch. Pretty intense depth of coverage, they wanted everything from class design to scaling to millions of users.

Design an object-oriented publish/subscribe notification service that supports user-topic subscriptions. Include APIs for subscribing, unsubscribing, publishing news, and acknowledging delivery. Cover class design, data modeling, concurrency, failure handling, and how you'd scale to millions of users.

“This was the whole interview basically.”

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Optiver·Software Engineer·Onsite - Coding / Algorithms

May 2026

Ninety-minute coding gauntlet at Optiver with three back-to-back problems spanning DP, heap design, and NP-hard approximation. The breadth was a lot to cover in the time given, and the third problem in particular felt like it was testing whether you'd panic or just commit to something reasonable.

Given an integer array and a threshold T, count the number of non-empty subsequences with sum at most T. Explain why brute force fails, justify your approach (DP or otherwise), and give complexity analysis.
Implement a job scheduler supporting INSERT, POP (smallest priority with stable tie-breaking), and DECREASE_KEY operations, all guaranteed O(log n), using a binary heap. Handle invalid and duplicate operations gracefully.
For selecting k items from n to minimize total score given item weights and pairwise penalties (an NP-hard problem), propose and implement a greedy or simulated annealing heuristic. Cover initialization, stopping criteria, and how you'd measure approximation quality against a baseline.

“The brute force explanation part tripped me up more than the actual DP.”

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Optiver·Data Scientist·Technical Phone Screen

May 2026

Optiver data scientist interview that's basically a live 30-minute trading game where you're betting against the interviewer across coin flips, dice rolls, and card draws. The rules change mid-game and you're expected to adapt on the fly, which is either exciting or terrifying depending on your relationship with probability.

Given quoted odds on a fair coin flip, how do you decide whether to bet and how much? What should you precompute so each round only takes a few seconds?
How do you price bets on events defined over the sum of two fair dice, and what's the key distribution fact that makes this fast?
How do you calculate the expected value of the product of drawn card values, and what property lets you avoid enumerating all outcomes?
What is the fair value of the sum of three cards drawn from a standard deck, and how does your estimate update as cards are revealed one at a time?
In the two-sided market segment, when should you buy at the ask, sell at the bid, or pass entirely?
The first revealed card is a King. How does your fair value for the three-card sum change, and does that move your decision relative to the original market?
Mid-game the interviewer adds a rule requiring a minimum bet of 10% of your bankroll every round. How does that change your approach?
If you had to quote the two-sided market on the three-card sum yourself, how would you set the width of your bid-ask spread?
You've found a bet with a large positive edge. Why might betting your entire bankroll on it still be a bad idea?
What is the Kelly criterion, why might it not be the right sizing rule for this specific game, and what would you use instead?

“This is the warm-up but don't underestimate it.”

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Optiver·Software Engineer·Technical Phone Screen

May 2026

Optiver software engineer interview with a trading systems flavor. They gave me an order matching problem that sounds straightforward until you actually have to think about the data structures under pressure.

Design and implement a price-based order matcher for unit-sized orders. Given an array of orders where each order is a [type, price] pair (type 1 = buy, type -1 = sell), process them in arrival order: a buy matches the cheapest resting sell at or below its price, a sell matches the most expensive resting buy at or above its price, and unmatched orders rest in the book. Return the sum of all executed trade prices. What data structures would you use, what's the time complexity, and how do you handle ties?

“The matching logic itself clicked pretty fast.”

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Optiver·Software Engineer·Recruiter / HR Screen

May 2026

Recruiter screen for a software engineer role at Optiver. Pretty light round, three questions, mostly just checking if you're a real human with actual reasons for being there.

Why do you want to be a software engineer?
Why Optiver specifically?
What do you do outside of work?

“I had an answer ready but it came out a bit generic.”

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Optiver·Software Engineer·Onsite - Coding / Algorithms

May 2026

Optiver software engineer round, pretty much a standard algorithms session. One question on interval merging, nothing too exotic, but the details matter more than you'd think.

Given an array of intervals, merge all overlapping ones and return the resulting non-overlapping set.

“Sort by start time first, that part came to me quickly.”

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Optiver·Data Scientist·Technical Phone Screen

May 2026

Optiver Data Scientist interview with a heavy focus on number sequence puzzles. Eight back-to-back pattern recognition problems, some straightforward, some genuinely tricky. The kind of session where you either love this stuff or you're quietly panicking the whole time.

Find the rule and the next term in the sequence: 12, 28, 36, 84, 88, 168, ?
Find the rule and the next term in the sequence: 4/3, 1, 5, 8, 23, 47, ?
Find the rule and the next term in the sequence: 3, 1, 2, 6, 12, 144, ?
Find the rule and the next term in the sequence: 1/5, 2/3, 3/11, 3/6, 5/17, 4/9, ?
Find the rule and the next term in the sequence: 7, 14, 24, 6, 12, 22, ?
Find the rule and the next term in the sequence: 19, 18, 20, 60, 15, 14, 16, ?
Find the rule and the next term in the sequence: 4, 2, 6, 6, 30, 150, ?
Find the rule and the next term in the sequence: 1, 3, 7, 17, 41, 99, ?

“Stared at this for way too long looking for an additive pattern before realizing you need to look at pairs.”

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Optiver·Software Engineer·Technical Phone Screen

May 2026

Optiver quant engineer interview with a pretty gnarly probability/statistics question built around regression diagnostics. One question, but it had a lot of moving parts and required you to actually reason through residual distributions rather than just recite definitions.

You have a scatter of (x, y) points with a fitted linear regression line. Rank these three events from most to least probable: (1) the regression overestimates y for a new x drawn uniformly from the training x-range; (2) a new (x, y) pair has y greater than 20; (3) the absolute residual for a new (x, y) pair exceeds 1.5 times the standard deviation of the training residuals. Justify your ranking using residual distribution properties like zero-mean, approximate normality, and homoscedasticity.

“This tripped me up more than I expected.”

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Optiver·Software Engineer·Technical Phone Screen

May 2026

Optiver software engineer interview had a mental math and pattern recognition section that felt more like a trading firm aptitude test than a typical coding screen. No calculator, no hints, just you and the sequences under pressure.

Find the next number in the sequence: 3, 6, 12, 24, ?
Find the next number in the sequence: 2, 3, 5, 7, 11, ?
Find the next number in the sequence: 1, 4, 9, 16, ?
Find the next number in the sequence: 1, 2, 4, 7, 11, 16, ? and also describe your fallback strategy if you can't immediately spot the pattern in any of these.

“This one was fine.”

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