Compute expected coin flips to meet on octagon
Company: Optiver
Role: Data Scientist
Category: Statistics & Math
Difficulty: medium
Interview Round: Technical Screen
Two independent particles start at opposite vertices (four edges apart) of a regular octagon. At each time step, flip one fair coin for each particle: heads moves one step clockwise, tails one step counterclockwise. What is the expected total number of coin flips required until the two particles occupy the same vertex?
Quick Answer: This question evaluates proficiency in stochastic processes, discrete-time random walks, Markov chain hitting times, and expected value computation within probabilistic modeling.