If you timeout on a significant number of questions, the code you wrote is not a few micro optimizations away from succeeding. The entire point is not to write the easy slow solution that is hundreds of thousands of times slower for large input sizes. This is much easier than getting the best solution, and hence less credit is given. I&#x27;m sorry that the instructions were not clear.<p>I agree with the author on some cases; Frequently, sites like hackerrank have a specific case  that causes Java Arrays.sort() to go  O(n^2) and  time out. Those feel dumb; there are many real life situations where quicksort is  fast on average and well worth using.<p>As for other things that hackerrank doesn&#x27;t test, I would say you should use hackerrank to screen applicants vs as an end-all-be-all.