Programming Challenges at Spotify


Choose a problem you like from our set of challenges, and read it carefully. If you're new here, you may also want to glance at the documentation on solving problems.


Your program must read from standard input and write to standard output and you can use any of our supported languages to solve the problem: C, C++, Go, Java, Objective-C, Python 2


Test your solution by sending off a message to with the problem ID as subject and your source code as an attachment. You will receive the results within minutes.

Here are the available problems, ordered by increasing difficulty:
Streaming Statistics hard
Toy Railway hard
Apparatus hard