N-Queens in Scala: How to Approach Algorithm Questions

Introduction

This episode will be a little different.

This video will teach you how to approach an algorithm-based, Google-style interview question in Scala with pure functional programming.

N-Queens is a classical computer science problem, where you need to find where you should place N chess queens on an NxN chess board, such that no two queens can attack each other. The problem asks for all valid possibilities. Depending on how big N is, there may be a lot.

This problem is usually solved with either backtracking in imperative code, or stack-based recursion. In this video, I show you a step-by-step algorithm in Scala, expressed as a purely functional program based on tail recursion.

This episode is a bit different because it’s a direct extract from the Scala & Functional Programming Interview Practice course, where — in its current March 2021 form — we deconstruct 50+ algorithm-based interview questions on various difficulty levels, in purely functional Scala. To my current knowledge, this is the only course on “cracking the coding interview” specifically for Scala programmers.

Conclusion

Thank you for watching!