Optiver Software Engineer Interview Experience — Breaking Down the Four-Part OA

The Optiver OA is honestly pretty hard. This part is 2 medium-difficulty coding problems plus 1 approximate-solution problem, all in 90 minutes. The problem types lean toward DP (dynamic programming) and heap (priority queue) style problems — testing mathematical modeling, data structure simulation, strategy backtesting, and statistical analysis skills.

Approach: before starting a problem, quickly figure out whether brute force or an optimized solution is feasible. You need to be fluent writing DP and heaps, and pay close attention to time complexity. The Approximate Solution problems are usually ones that can't be solved exactly — you approximate the answer using greedy methods or simulated annealing.

Beat the Odds Probability

30 questions, 90 seconds each, mainly testing your understanding and application of basic probability theory. It covers expected value, conditional probability, probability distributions, gambling odds, combining multiple questions, and so on — common examples are things like "sum of two dice," "odds calculation," "risk/reward ratio."

Approach: speed is key. A lot of questions don't need the full formula written out — if you can use a known probability formula, a distribution table, or a quick mental-math trick, it's a lot faster.

Number Logic Test

This is just number-sequence pattern finding — no calculator allowed, only pen and paper, 25 minutes for 26 questions.

Approach: get familiar with common patterns (add/subtract/multiply/divide, squares, primes, alternating changes, repeating patterns). If you don't see it at first glance, skip it — don't get stuck on one question.

Zap-N

This is a reaction + memory mini-game, 9 small stages — things like remembering numbers, switching between shapes, and so on. It mainly tests your reaction speed, memory, and task-switching ability.

Approach: practice similar brain games in your spare time, like Lumosity or Brain Wars, to get used to that feeling of quickly switching attention.

For reference on what comes after the OA — overall, once you pass the OA, the interview is math questions plus code, and for SDE positions there's also SD