Combinatorics

Overview

About combinatorics questions in quant interviews

Counting arguments, permutations and combinations, inclusion-exclusion, and the discrete-probability setups that open trader and researcher interviews alike.

How to study this topic

A path that works

1. 1

   Start with the intro set

   This topic skips the warm-up. Questions land at medium difficulty and above, so read each prompt twice before solving.

2. 2

   Drill the medium tier next

   1 medium question sit in the sweet spot where most interview questions cluster. Time yourself, then redo any you missed two days later.

3. 3

   Stress-test on hard problems

   2 hard questions simulate the on-site round. Skip looking at solutions for at least 20 minutes, then write up your approach.