Jane Street DSA Interview Questions

What Jane Street asks in the DSA round

Jane Street's loop is probability and mental-math first, with algorithm rounds that reward clear reasoning over memorised patterns. Expect estimation games and thinking out loud.

Across the 16 questions on this page, the weight sits on these patterns:

• Simulation — 4 questions
• Design — 2 questions · read the design data structure guide
• Dynamic Programming — 2 questions · read the dynamic programming guide
• Hash Table — 2 questions
• Trie — 2 questions
• Linked List — 1 question · read the reversal of linked list (in-place) guide
• Math — 1 question
• Stack — 1 question

How to prepare for the Jane Street interview

1. 1. Start at the top of the list above. The patterns are ordered by how often Jane Street uses them, so the first two or three buy you the most coverage per hour.
2. 2. Solve by pattern, not at random. Doing eight simulation problems in a row is what makes the ninth recognisable in an interview — jumping between topics does not.
3. 3. Tick problems off as you go so the gaps are visible. The per-pattern counts tell you which Jane Street topic you have actually covered.
4. 4. Write the approach before the code. Jane Street interviews are judged on the reasoning as much as the working solution.
5. 5. Pair this with the pattern guides when a topic is new, and the system design sheet if the role is senior enough to have that round.
6. 6. If this is a campus or off-campus drive rather than a lateral move, the placement preparation guide covers the stages around the DSA round — aptitude, core subjects and the HR interview — in the order they actually happen.

Jane Street interview questions — FAQ

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