Leading up to my current job, virtually none. However, at my current job (Firebase), it now makes up a significant percentage of what I do. The way I've described it to friends is: "You know how most companies ask you tree traversal/sorting/search questions in an interview, then when you show up for work the first day, your job turns out to be 'add this button to this web form'? We actually work on those algorithm problems." It helps that we are an infrastructure company and that our user interface is an API.

If this is something you're looking for, my recommendation is to look at either large companies that have large infrastructure needs (Google, Facebook, Twitter, Amazon, LinkedIn, etc.) or small infrastructure-related startups, depending on your preferred working environment. If the hard parts of your job are offloaded to the database/language runtime/middleware, look for companies that work on databases, language runtimes or middleware. And in the interview, ask them for examples of hard problems that they have solved.

Also, I have absolutely nothing against the companies that don't do this kind of work. In fact, Firebase exists so others don't have to do this kind of work. This is just an observation that occasionally, the skillset tested in these interviews is not in line with the responsibilities a successful candidate will end up having, so make sure you ask.