This sounds like what a lot of companies do - except the scaled problem with this approach (and the certification approach of the grandparent) is that most comp

This sounds like what a lot of companies do - except the scaled problem with this approach (and the certification approach of the grandparent) is that most companies want to avoid candidates who've memorized a specific solution, as then they don't get any data about whether they can code anything aside from what was memorized. The other problem is that implementing bubble sort will tell you about their skills in a particular dimension, but being a software engineer these days may look very different depending on the job.