Computer Science Interview Questions with C++ Solutions

Since when is tree traversal "pure academic"? It's like one of the most mundane things, it's like sorting or hashing, it's something you run into on a regular basis, and the fact that it's wrapped into a library doesn't give you an excuse to not know it, because that knowledge is necessary to use the library correctly (i.e. answering questions like "do I use TreeSet or HashSet here?").

It irritates me because it's not even remotely "academic". Category theory is academic, this is mundane things. It probably is the bare minimum one has to know if they hope to work on anything interesting.

It's very difficult to find questions of the correct difficulty for an interview that don't require arbitrary knowledge that the candidate might not have.

The binary tree question has a short definition, requires only knowledge that any candidate will have, and is easy for any logical thinker.

If I am administering a practical test for a junior programmer position, as in, a fresh graduate, the binary tree test is a great one.

I put them in front of an IDE, sit with them, and ask them to write a unbalanced binary tree container with insert, find and delete functions.

Watching a candidate do this tests basic implementation skill, API design, debugging and testing methodology. By the end of it, I have a pretty good idea if they will make a good hire.

>Implement a simple linked list in C (not C++). It can be compiled on a C++ compiler, but do not use any feature of C++.

Er, which standard of C?

There's no harm in brushing up on CS 101 questions, but I wish more candidates spent time preparing for questions about code quality.

It depends. In many cases it's impossible to give sufficient context to provide a real-world problem that will let the candidate show their understanding of algorithms and data structures. Sometimes it's necessary to ask these sorts of questions in isolation, without a concrete problem. Not least, sometimes a real world problem is better solved in a different way anyway, which subverts the intent.

Understand, most real world programming jobs don't need in-depth knowledge of algorithms and data structures. Most real world programming jobs are implementing the algorithms devised by someone else, using data structures that are "obviously" the right structure for the job. When companies are asking these sorts of questions they usually have a somewhat inflated view of their own importance. Either that, or those interviewing have no real idea about the work done by their programmers.

The very best interviewers, when using these questions, don't worry too much about the detail of the solution, but in the discussion of the pros, cons, benefits, drawbacks, and possible development of the code in context. Even with FizzBuzz there is much to be explored once a coder has written it.