Optiver HackerRank Quantitative Assessment

Hi monkeys,

I moved past the resume screen for Optiver's junior quant trading position and was wondering what to expect from their online HackerRank quantitative assessment. Namely, should I be brushing up on my coding skills or is my prep time better spent drilling mental math problems? The fact that it's called a "quantitative assessment" leads me to believe that it's probably the latter but I wanted to confirm with some monkeys in the industry.

Thanks in advance,

KM