[nickbauman]

Knowing the implementation of a specific algorithm is much less important than knowing what class of problem you're facing, where and how to look up the details of algorithms that could help you and how to work well with others to get the work done. If your employer uses hackerrank to choose candidates, you really don't want to work there. People who do those things well are often the worst kind of people to hire: they're really good at certain types of problems but suck at almost everything else. I end up cleaning up systems after these people all the time everywhere I encounter them in the workplace.

[lprubin]

Exactly this. The hiring process cuts both ways. Unless you're desperate, you should also be evaluating your employer and the quickest way for me to walk away is to filter candidates through something like hackerrank rather then something much more applicable to what I'd actually be doing as a programmer at the company. It shows me a big disconnect between hiring and the day to day and gives me no indication on the skill level of the team I'll be working with.

[tspike]

You are overstating your case. Hackerrank is useful as a pre-screen. Give a fizz-buzz type problem on Hackerrank, then proceed with the normal interview process. The kinds of people you are describing would be filtered out in the subsequent interviews.

[nickbauman]

I can only hope you're right. The tone of the OP doesn't directly support either/or however.