Optimization Interview Questions
Optimization is where math meets money on a trading desk: almost every quant decision is secretly an argmax or argmin. This playlist builds you from the bedrock ideas (convexity, first-order conditions, the Hessian/second-order test, Lagrange multipliers and KKT) up through the workhorses you will a
How to think about optimization questions
Optimization problems share one skeleton: you want the best value subject to constraints, and the trick is never brute force — it's recognizing the shape of the landscape so the optimum reveals where it must sit.
CONVEXITY IS THE GIFT
If the objective is convex and the feasible set is convex, any local minimum is the global one — so you just chase the gradient downhill until it vanishes. Half the battle in these problems is spotting that hidden convexity (or a substitution that creates it).
PRICE THE CONSTRAINTS
To handle constraints, attach a Lagrange multiplier to each — the marginal value of relaxing it. At the optimum the objective's gradient is a combination of the constraint gradients, and the KKT conditions package equality, inequality, and complementary-slackness cases into one tidy system.
Work this set and the question becomes reflexive: is this convex, and what is each constraint worth at the margin?
Optimization questions (92)
- Minimum Variance Portfolio of Two Correlated Assets
- Newton's Method for Square Roots
- Finding and Proving a Minimum of a Two-Variable Polynomial
- Minimum Variance Portfolio for Two Assets
- Minimum of x^x on (0, 1]
- Maximizing a Quadratic Form
- Minimum-Variance Portfolio with Two Uncorrelated Assets
- Most Likely Poisson Parameter
- Arbitrage in Betting Markets
- Maximizing the Product of Stack Sizes
- Mean as the Minimizer of Squared Loss
- Optimal Bet Sizing via the Kelly Criterion
- Minimum Cost Path With Color Switching
- Monte Carlo Integration
- Optimal Hedge Ratio for Variance Minimization
- Optimal Two-Signal Trading Rule
- Burger Flipper
- Optimal Linear Forecast Combination
- Partition Array into Exactly m Segments to Maximize Sum
- Constrained Least Squares Estimation of Triangle Side Lengths
- Minimum Variance Mixed Estimator
- Two Eggs, d Drops: Maximum Floors
- Cross-Section vs Time-Series Allocation
- Numerical Function Minimization via Gradient Descent
- Partition Array to Minimize Maximum Subarray Variance
- Kelly Criterion With a Risk-Free Rate
- Problems With L0 Regularization
- OLS vs. Median Regression: Why Prefer OLS?
- Optimal Apartment Rental Pricing
- Beta-Neutral Portfolio Variance
- Geometric Median via Weiszfeld's Algorithm
- Top-K Alpha Selection with Diversity Penalty
- Kelly Bet Sizing with a Drawdown Constraint
- Relaxing Constraints in Infeasible Optimization
- Maximum Path Sum in a Number Triangle
- Portfolio Optimization with Alpha Signals
- Optimal Tick Improvement for a Market Maker
- Minimum Match Probability for Biased Dice
- Capital Allocation Across Strategies
- Revenue Optimization with Poisson Demand
- Balls in Two Boxes Optimization
- Alpha to Portfolio Weights Under Turnover Constraint
- Minimum Variance Contiguous Partitioning
- Bloom Filter Sizing and Optimal Hash Count
- Capacity Analysis for a Mid-Frequency Strategy
- Step Function Fitting with Dynamic Programming
- Ant Traversing a Unit Cube
- Rank-Transformed Signals vs. Raw Signals for Portfolio Sharpe
- Maximum Drawdown in Linear Time
- Bridge and Torch with a Pairing Constraint
- Inventory-Averse Quoting with Quadratic Penalty
- Maximizing Taxi Driver Revenue
- Kelly Criterion for Optimal Bet Sizing
- Newton's Method: Quadratic Convergence Proof and Stopping Rule
- Arbitrage Detection in Currency Exchange Graphs
- Mean-Variance Optimization via Linear Algebra
- Beta-Neutral Portfolio Adjustment
- Optimal Accept-Reject Threshold for Fills
- KKT Conditions for Quadratic Programs
- Correlation Network: Connected Components, Threshold Selection, and Diversification
- Optimal Stopping with Uniform Draws
- Optimal Spread with Adverse Selection
- Shrinkage Covariance Estimator for Mean-Variance Portfolios
- Optimal Stopping on a Fair Coin Random Walk
- Optimal Trade-to-Fill Assignment via the Hungarian Algorithm
- Mean-Variance Portfolio Optimization
- Target-Sum Die Game with Per-Roll Cost
- Optimal Market Making with Mean-Reverting Midprice and Inventory Cost
- Fractional Kelly Under Drawdown Constraint
- Key-Rate DV01 Hedging With Variance Minimization
- Knowledge Gradient for Two Bernoulli Arms
- Kelly Criterion With Known Edge
- Constrained Mean-Variance Portfolio Optimization
- MDP Formulation for Stock Trading
- Maker/Taker Fees in Break-Even Spread
- Optimal Weights for Five Signals with Unknown Covariance
- Bayesian One-Step Lookahead Index for a Two-Armed Bandit
- Egg Drop Problem
- Kelly Criterion with Proportional Transaction Costs
- Minimum Variance Portfolio with Factor Model
- Transporting Apples with a Hungry Truck Driver
- Optimal Interval Scoring Under a Coverage Constraint
- PCA Factor Hedging and Residual Variance Minimization
- Posterior-Optimal Kelly Fraction
- Maximum Sharpe Ratio Portfolio with Uncorrelated Assets
- Impact-Aware Execution Scheduling
- Kelly Criterion for Multi-Match Bet Sizing
- Signal Decay, Holding Period Overlap, and Net Sharpe Optimization
- Power of Two Choices Load Balancing
- Optimal Tender Price for a Block Trade
- Optimal Winsorization Threshold for a Contaminated Signal
- Optimal Venue Allocation with Maker Rebates
Optimization interview questions FAQ
What kind of optimization questions show up in quant interviews?
This page collects 92 optimization problems that recur in quant trading and research interviews, each with a full worked solution and the intuition behind it. They range from quick warmups to the harder variants firms use to separate candidates.
How hard are optimization interview questions?
The set spans 2 easy, 53 medium and 37 hard problems. Most sit at medium difficulty — a few minutes of clean reasoning — with a harder tail that rewards knowing the canonical approach rather than grinding.
How should I practice optimization for quant interviews?
Work through them by difficulty, starting just below your level, and write the solution out before checking. 13 are free to open with the full worked solution, so you can judge the quality first. Focus on the recurring patterns rather than memorizing answers — the same handful of ideas generate most variants.
Are these real quant interview questions?
They are a curated set drawn from our problem bank — the kind of optimization question that actually appears in quant interviews, rewritten for clarity with solutions we author ourselves. We don't claim any single wording is verbatim, and every problem carries a full solution.