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Start date: Oct. 9, 2021, 5 p.m. UTC
Move coins between the given stacks to obtain a stack with the maximum possible number of coins.

Knock knock, trick or treat?

The first 3 developers to solve the challenge perfectly in the least amount of time will be added to the Codility Hall of Fame, winning $25 Amazon gift cards. You can use them to treat yourself to some goodies for Halloween.

Once the Spooktober Challenge has ended (on October 23rd), you will still be able to take the challenge, and gain certificates, but will no longer be in the running for prizes.

Good luck solving this challenge!

About Codility

We help engineering leaders hire great software developers into their teams by evaluating technical skills in an unbiased way. We’re committed to levelling the playing field by building a platform that provides equal opportunity to all developers worldwide. Interested in joining us? We’re currently hiring engineers to work remotely from all over Europe.

The challenge is now over, but you may still practice on this task. Below, you can also find a video with explanation of possible solutions for the task:

View careers


2961 started 130 silver awards 308 golden awards

Hall of fame:

乐平 汪
Time: 3 minutes
Andrei Navumenka
Time: 6 minutes
Md Abedin
Time: 6 minutes