Company Description

Kaltio Technologies, an innovative and challenging startup company, develops world-class messaging solutions to mobile and Internet of Things markets. We have a great team of experienced developers, fantastic atmosphere and a very nice office at downtown Oulu (with game consoles etc.). Also we have plenty of annual refreshing events.

We can offer you an opportunity to learn cutting-edge technologies used to create large distributed systems, scaling to hundreds of millions of users. Multiple positions are open to self-driven and motivated people.

A list of skills useful in these positions is presented below. You’re not expected to have mastered all of them but you should be comfortable with at least a few:


Android and/or IOS Developer

  • Experienced in at least one of the languages: Java, JavaScript, C, C Sharp
  • Good understanding of RESTful web services
  • Basic knowledge of distributed architectures

With your application, we’d like you to present a working solution to the following problem, implemented in any language you like:

Which of these data structures has better performance when an entry needs to be deleted, a hash table or an array? Why?

Please include your unit tests code with application (for verifying your answer). Send your application with CV via email by the end of march.