Quant Guide
Quant traders and quant researchers both face challenging interviews that test far more than basic math. These selected problems guide quants to practice the concepts that matter most. Unlike discretionary traders, quant traders rely on mathematical models and coding rather than intuition. Their interviews emphasize fast problem-solving with probability puzzles, brainteasers, math challenges, and coding tasks. Quant researchers focus more deeply on models and longer-term projects, which is why their knowledge of statistics, linear algebra, and advanced programming is assessed.
| Brain Teasers | |||
|---|---|---|---|
| 100 Light Bulbs | Symmetry | Medium | |
| Back to Starting Point | Logical | Medium | |
| Birthday Puzzle #2 | Logical | Hard | |
| Calendar Dice | Out of the Box | Medium | |
| Clocks and Hands | Logical | Medium | |
| Door to Offer | Out of the Box | Hard | |
| Escape Plan | Out of the Box | Medium | |
| Farmers' Land | Logical | Medium | |
| First Person to Say 50 | Logical | Medium | |
| Fishermen | Logical | Hard | |
| Fox vs. Duck | Logical | Medium |
Example
|
| Horse Race | Logical | Medium | |
| House of Cards | Summation | Medium | |
| How Many Twos | Simplification | Medium | |
| Infinite Chessboard | Out of the Box | Hard | |
| Knights and Knaves | Logical | Easy | |
| Pirates Dividing a Treasure | Simplification | Medium |
Example
|
| Prisoner Problem #1 | Modular | Hard | |
| Prisoner Problem #2 | Modular | Hard | |
| Rabbit Climbing the Stairs | Logical | Easy | |
| Salary Voting | Logical | Medium | |
| Sandglass | Logical | Medium | |
| Subset of Numbers | Logical | Hard | |
| Tennis Match Mystery | Logical | Hard | |
| The King's Party | Out of the Box | Medium |
Example
|
| The Last Chocolate Game | Logical | Hard | |
| Trailing Zeros | Logical | Medium | |
| Transfer 3000 Apples | Logical | Hard | |
| Two Glass Balls | Summation | Medium | |
| Waiting for the Train | Logical | Medium | |
| Water and Wine | Logical | Easy | |
| Water Jugs | Logical | Medium | |
| Weighing Blocks | Logical | Easy | |
| Which Day | Logical | Hard |
| Probability and Statistics | |||
|---|---|---|---|
| 100-Sided Die | Expected Value | Hard | |
| Aces for All | Combinatorial Analysis | Easy | |
| Animal Migrations | Markov Chain Probability | Easy | |
| Athletic Cats | Conditional Probability | Medium | |
| Basketball Practice #1 | Expected Value | Medium | |
| Basketball Practice #2 | Expected Value | Hard | |
| Beat the Odds | Game Puzzle | Hard | |
| Biased Coin #1 | Expected Value | Medium | |
| Biased Coin #4 | Expected Value | Medium | |
| Bold Betting Strategy | Markov Chain Probability | Medium | |
| Coin Toss | Conditional Probability | Medium | |
| Dice Game | Expected Value | Hard | |
| Dice vs Coins | Expected Value | Medium | |
| Dice With Same Numbers | Expected Value | Medium |
Example
|
| Dominant Game | Markov Chain Probability | Hard | |
| Drunk Student #2 | Expected Value | Medium | |
| Exponential Distribution #1 | Expected Value | Medium | |
| Exponential Distribution #2 | General | Medium | |
| First to Heads | Conditional Probability | Medium | |
| Flip 4 Coins | Expected Value | Medium | |
| Flowers in Bloom | Expected Value | Medium | |
| Free Ticket | Expected Value | Hard | |
| Going to the Beach #2 | General | Hard | |
| Higher Card | General | Medium | |
| How Many Children | General | Hard | |
| How Many Pairs | Combinatorial Analysis | Hard | |
| Jumping Robots | General | Hard | |
| Meeting Your Friend | Combinatorial Analysis | Medium | |
| Old Phone #2 | General | Hard | |
| Old Scale | Combinatorial Analysis | Easy | |
| Optimal Spread | General | Hard | |
| Overbooked Flight | Combinatorial Analysis | Medium | |
| Painted Cube | Conditional Probability | Hard | |
| Parking Meter | Markov Chain Probability | Easy | |
| Picking Balls #2 | Combinatorial Analysis | Medium | |
| Picking Balls #3 | Combinatorial Analysis | Medium | |
| Picking Tiles | Markov Chain Probability | Easy | |
| Racing Cars | Conditional Probability | Medium | |
| Random Ant | Markov Chain Probability | Medium |
Example
|
| Region Spinner | Markov Chain Probability | Easy | |
| Running Rabbit | Combinatorial Analysis | Medium | |
| Second Heads | Conditional Probability | Medium | |
| Specific Card #2 | Combinatorial Analysis | Medium | |
| Spin in Two Regions | Expected Value | Medium | |
| Tennis Game | General | Medium |
Example
|
| Tennis Match: Win in 2 or 3 Sets | General | Medium | |
| Tennis Odds | Game Puzzle | Hard | |
| The Drunkard's Walk | Markov Chain Probability | Hard | |
| The Highest Face | Expected Value | Medium | |
| Three Blue Orbs | Expected Value | Medium | |
| Throw a 6 #2 | Expected Value | Medium | |
| Throw a 6 #3 | Expected Value | Hard | |
| Throw Until Matched | Expected Value | Medium |
Example
|
| Top 2000 Songs | Markov Chain Probability | Medium | |
| Toy Collection #1 | Expected Value | Medium | |
| Toy Collection #2 | Expected Value | Hard | |
| Two Consecutive Fives | Expected Value | Medium | |
| Two Dice Difference | Expected Value | Easy | |
| Two Rolls Payoff | Expected Value | Easy | |
| Unfair Heads #2 | Conditional Probability | Medium | |
| Uniform Distribution #1 | Expected Value | Hard | |
| Vacant Room | Conditional Probability | Hard | |
| Which Die Was It | Conditional Probability | Hard |
| Programming | |||
|---|---|---|---|
| All Pairs | Array and List Processing | Easy |
Example
|
| All Vowels | String Manipulation | Easy | |
| Arithmetic Mean | Array and List Processing | Hard | |
| Binary Search Tree (BST) | Array and List Processing | Hard | |
| Circular Queue Implementation | Other | Hard | |
| Common Prefix Algorithm | String Manipulation | Medium | |
| Consecutive Letters | String Manipulation | Medium | |
| Count Number of Homogenous Substrings | String Manipulation | Medium | |
| Dijkstra's Algorithm #1 | Graphs | Hard |
Example
|
| Dijkstra's Algorithm #2 | Graphs | Hard | |
| Drawing a Blue 3 | Mathematical Problems | Medium | |
| Empty Number of Boxes | Mathematical Problems | Medium | |
| Find All Paths | Graphs | Hard | |
| Find the Missing Number | Array and List Processing | Easy | |
| Finding the Largest Possible Number | Array and List Processing | Easy | |
| Group Anagrams | String Manipulation | Medium | |
| Last Node of Singly Linked List | Other | Medium | |
| Longest Common Subsequence (LCS) | Array and List Processing | Medium |
Example
|
| Minimum Spanning Tree (MST) | Graphs | Hard | |
| Optimal Stopping Strategy | Mathematical Problems | Medium | |
| Palindrome Checker | String Manipulation | Medium | |
| Pricing Accuracy | Mathematical Problems | Medium | |
| Prime Number Generator | Mathematical Problems | Medium | |
| Priority Queue Using Heaps | Other | Hard |
Example
|
| Roulette Table | Mathematical Problems | Medium | |
| Smallest String | String Manipulation | Easy | |
| Sorting Without Sort() | Array and List Processing | Hard | |
| Subarray Sum Equals Zero | Array and List Processing | Medium | |
| Sudoku | Array and List Processing | Hard | |
| Summing Up Strings #1 | String Manipulation | Hard | |
| Summing Up Strings #2 | String Manipulation | Hard | |
| Top 2000 Songs | Mathematical Problems | Medium | |
| Weather API Data Analyzer | Other | Hard | |
| Word Frequency | String Manipulation | Easy | |
| Words in a String | String Manipulation | Medium |
| Math Questions | |||
|---|---|---|---|
| Boats on a River | General | Hard | |
| Choosing Blocks | General | Easy | |
| Escalator Steps | General | Medium | |
| How Many Dogs | General | Medium | |
| Inflate Rate | General | Hard | |
| Magic 37 | General | Hard | |
| Number of Pigs | General | Easy | |
| Product of Unknowns #1 | Solving Unknowns | Hard | |
| Radius of a Circle | General | Hard | |
| River Length #1 | General | Medium | |
| River Length #2 | General | Medium | |
| Sequences | General | Easy | |
| Sharing a Glass | General | Easy | |
| Sheep Runs Home | General | Hard | |
| Spread Set | General | Hard | |
| Squares On Chessboard | General | Medium | |
| System of Weights | Solving Unknowns | Medium | |
| Unfolded Box | General | Hard | |
| Upstream or Downstream | General | Medium |