This stuff seems actually quite difficult to me. For example on one silly programming contest problem[0] there's a cluster of users from about 6th place to abou

This stuff seems actually quite difficult to me. For example on one silly programming contest problem[0] there's a cluster of users from about 6th place to about 21st place who are basically reading memory sequentially as fast as they can using some simple loop that does 2 or more 32-byte loads into vector registers and then does some trivial calculations that can be done concurrently with the next loads (this is maybe 20 instructions if you choose to do a lot of loads per iteration, way fewer than that if you do just 1 or 2). There is also a small group of users who are going significantly faster! The top solution seems to be reading RAM 20% faster than a loop whose instructions look fine to me. [0]: https://highload.fun/tasks/5/leaderboard https://highload.fun/tasks/5/leaderboard