Headlands Technologies Interview Questions
56 Headlands-tagged problems spanning probability and brain-teasers, expectation/EV, statistics and regression, and production-grade algorithmic coding for quant research and dev roles.
Inside the Headlands Technologies interview
Headlands Technologies is a global quantitative and algorithmic trading firm whose edge is fully systematic. Its interviews probe whether you can reason cleanly under uncertainty and turn that reasoning into correct, efficient code — blending probability, statistics, and algorithmic engineering.
What they test
The largest block is algorithmic coding — streaming data structures, sliding-window medians, as-of joins, matching-engine and order-management design — the kind of low-latency, correctness-critical work a systematic shop runs on. Around it sits a strong probability and brain-teaser core (optimal stopping, random walks, EV of dice and card games) and a statistics & regression layer (Bayesian updating, AR(1)/unit roots, ridge vs. lasso, OLS vs. total least squares).
The recurring shapes
Many questions reward an online / streaming mindset: compute a running statistic in one pass rather than recomputing it. Welford-style covariance and rolling medians are the canonical examples — keep summary state and update it as each element arrives.
How to approach
State assumptions out loud, then drive to the cleanest exact answer: set up an expectation or recursion for the probability puzzles, name the estimator and its bias/variance for the stats problems, and lead with complexity on the coding ones. Headlands cares as much about how you reason as the final number, so narrate the trade-offs.
The mix leans medium, with a meaningful block of hard streaming-coding and stochastic problems and a handful of easy warm-ups to get rolling.
Headlands Technologies coding questions (23)
- Streaming Queue with Mean and Snapshots
- Maximum Concurrent Orders in an Interval
- As-Of Join on a Timestamped Table
- Merge K Sorted Streams with Bounded Concurrency
- Top K Tickers by Notional
- Order Management API with Sublinear Queries
- Find the First Failing Transaction
- Recursive Sum 1 to N with Overflow and Stack Limits
- Mutable Default Arguments in Python
- Job Runner: Summarize Job Chains from a Daily Log
- Rolling Median in a Streaming Window
- Sliding Window Median Data Structure
- Order Matching Engine Design
- Minimum-Length Subarray With Sum at Least S
- Sliding Window Maximum with a Monotonic Deque
- Bucket Sort for Uniform Samples
- K-th Smallest Element in a Sorted Matrix
- All-Pairs Two-Sum With Stable Ordering
- Minimum Cost of a Matrix Chain Product
- Maximum Concurrent Intervals Over a Small Integer Range
- Optimal Worker-Task Assignment
- Maximum Stock Trading Profit with Unlimited Transactions
- Counting Substrings of Identical Characters
Headlands Technologies probability questions (7)
Headlands Technologies statistics questions (6)
Headlands Technologies regression questions (5)
Headlands Technologies expected value questions (5)
Headlands Technologies combinatorics questions (3)
Headlands Technologies brain teasers questions (3)
Headlands Technologies optimization questions (2)
Headlands Technologies game theory questions (1)
Headlands Technologies stochastic processes questions (1)
Headlands Technologies interview FAQ
What kind of questions does Headlands Technologies ask in quant interviews?
Candidates most often report coding, probability and statistics questions. This page collects 56 of them, 16 stamped with the month they were last reported — each with a full worked solution.
How hard are Headlands Technologies interview questions?
The set spans 7 easy, 33 medium and 16 hard problems. Most sit at medium difficulty — solvable in a few minutes with clean reasoning — with a harder tail that rewards knowing the canonical tricks.
How do I prepare for the Headlands Technologies quant interview?
Work through this set by topic (use the sidebar), starting from your weakest area. 6 problems are free to open with their full solution, so you can judge the quality before anything else. Then walk the full Headlands Technologies interview guide for the round-by-round funnel and the online assessment.
Are these the actual Headlands Technologies interview questions?
They are built from candidate-reported Headlands Technologies questions. We rewrite each prompt for clarity and author the worked solutions ourselves — we don't claim the wording is verbatim, and we never invent questions or recycle generic lists. 16 of 56 carry the month they were last reported.