On the evening of Saturday, November 23rd, we contributed, as is proper, to the celebration of the 50th anniversary of the British series Doctor Who with a contest on the theme of the Doctor. Intergalactic and somewhat crazy, this challenge gave us the opportunity to propose new kinds of problems that you took, so it seems, as much pleasure in resolving as we had in imagining the puzzles.

In terms of user interface, there were several innovations. On the one hand, there was the arrival of the personal section – “My Console”, with which you could access the challenge and the leaderboard (we also minimized losses regarding those who didn’t find in their email the link for connecting to the challenge). Also of interest was the possibility of sharing your progression on your CodinGame public profile. On the other hand, autocompletion was available in the IDE and many of you appreciated it on the spot.

In the end, most of you got through the first exercise and the second, traditionally, gave you a harder time. Reading your responses, we could see that there were sometimes certain small concerns regarding the interpretation of the statements, but on the whole, the idea was understood.

So, bravo to everyone, and thanks for participating!

The Exercises

1st exercise: Doctor Who – The Gift

Here we started with an algorithmic warm-up lap. The action takes place in 4798 at the heart of the Ood civilization. The mission of the Doctor: to determine the price of a ceremonial gift while respecting the budget limit of each participant and while displaying as much equality as possible. This problem could be resolved very quickly if one found the right angle of attack that consisted of charging as a priority those who had the lesser budget (yes, it was).

Solve The Gift puzzle!

2nd exercise: Doctor Who – Music Sheets

This one involved thwarting the plans of the infamous Graske and sending him to the confines of the universe by replaying a musical score. This second problem wasn’t a purely algorithmic exercise. The resolution was in the recognition of an image – a first for CodinGame. You had to be as clever as possible and produce quite a lot of code. Among the different techniques used, some set off on a detection of lines of the score, while others preferred to concentrate on the spotting of the tails of the musical notes. In brief, there were many possible implementations and it came down to who would be the most imaginative.

NB: Needless to specify, for the 2nd problem, there was no point in just displaying the results of the test cases as a solution… Indeed, to be clear, the validators are in the end always different from the tests cases we give in the puzzles statements.

Solve Music Sheets puzzle!

The Results

The first to achieve a 100% was HappyHamster (01:28:49), in PHP, what’s more. He was followed by Manger (01:55:33 in C#) and by zerkman (01:58:31 in C). Hats off to all three!

The rankings

Take a look at the rankings and the leaderboard by languages with links to the source codes of the participants here.

As promised, the participants in the top 20 of the global rankings win a t-shirt and the first in each class by language who has a score greater than or equal to a 50% leave with a Raspberry Pi. Therefore, some who chose less used languages were able to kill two birds with one stone: t-shirt + RPi.

read STDIN T-Shirt

prize: raspberry pi


The registered come from more than 66 countries. The top ten most represented countries: France, India, Morocco, Russia, Ukraine, Tunisia, Brasil, the USA, the UK, and Belgium.

With this challenge, one is more in the realm of the qualitative than the quantitative, since from the 2,200 registered, we count 1,167 finishers, of which 871 managed to obtain a score >0.

Results of Doctor Who coding contest

Next Online Coding Challenge on the 25th of January 2014. Save the date!

Mission to Mars Coding Challenge teaser