Two Sigma Software Engineer interview questions

Online Hackerrank was very easy, was given 3 hours to solve two classic CS problems. Was able to solve both, check them, and even add comments to the code, with 2.5 hours still to spare. Phone interview was bad. Interviewer was Chinese and could barely speak coherent English. Audio quality was also terrible as it was an international phone call. Asked a few OS questions, then a main coding question. I started solving the coding question optimally but interviewer was telling me my solution was 'wrong', when what he really meant was he wanted a simpler-and-less-efficient solution. Led to a lot of confusion. Somehow I passed and went to onsite. Questions seemed reasonable, but not enough time was given to solve them even though I knew the solutions. And I was given a macbook with really awkwardly spaced-out keys, unfamiliar key shortcuts, and no mouse, so I was constantly making typos or struggling to use the mac-style touchpad. Not happy with the overall process, seemed a lot more luck-based than skill-based.