Tips on online coding test- Codility and HackerRank

Online coding test is the most popular technical screening in Japan. There are a number of coding test platforms that companies use. We have seen that majority of the companies either use Codility or HackerRank.

  1. Codility – “Codility is a software platform that helps technical recruiters run remote interviews and hire strong engineers.” – Take a practice test here
  2. HackerRank – “HackerRank is the market-leading technical assessment and remote interview solution for hiring developers. Learn how to hire technical talent from anywhere!” – Take a practice test here

For you to understand what these coding platforms are about, we recommend you to take a sample practice test using the link above. A general introduction to Codility and HackerRank is that:

  • There are around 1-3 questions that you must solve in usually 1-2 hours.
  • After you receive a link to the test, you have around 1 week to start the test. You can start the test anytime, but once you click start test, you must complete the test in one sitting. It may be possible to ask for extension for the deadline by contacting the HR/TA you are in contact with.
  • The problems are mainly algorithm-based questions, often basic questions that you have studied in university, but may have forgotten if you have worked as a Software Engineer for over 2-3 years.

How to prepare for coding test

Coding tests are mostly algorithm and data structure questions, on topics like binary trees, hash table, arrays, etc. The difficulty itself is not too high, but they test the basics of algorithms and data structures, which many have forgotten. You can prepare for coding test by:

  1. You can start by reading the textbooks mentioned in our previous topic: Recommended textbooks to read
  2. You can take the online lessons by Codility here OR HackerRank practices at here
  3. Take Leetcode practices questions and look at how your answers compare to their solutions
  4. We recommend you to watch Code Dojo’s video playlist on Data Structures and Algorithms at here

Tips for passing coding test

  • Allocate a set time for each question and if you are running out of time, compile some sort a solution. A poor solution is better than no solution
  • If you have time, write a simple test (Unit Test) to make sure your solution works.
  • *This may violate policies for some companies, but there is no specific policy for this from Codility or HackerRank. Have a textbook near you to quickly check syntaxes or simple algorithm concepts.