Fantastic Bits has been a lot of fun. Congratulations again to the three winners Magus, reCurse and pb4! They have been eager to explain how they managed to win. Ready to become a boss in bot programming? Read on…

He’s a legend on the platform but had never won a contest before. Magus finally did it with Fantastic Bits!

Magus postmortem

Introduction

Fantastic Bits was by far the hardest challenge ever created by CodinGame. It is simply impossible to just hope reaching the top 10 without putting everything you know on the table. It’s a long, hard and dangerous road.

When I first saw the rules of the game, I immediately knew what method I was going to use for my AI.

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His first contest was Hypersonic, and he finished 6th. He got the second place in Fantastic Bits. All we can expect from reCurse is to win next contest.

reCurse postmortem

The AI I have created for the Fantastic Bits contest was, like most players in the top, based on accomplishing three things:

  1. Re-code a full simulation of the game mechanics to accurately predict the result of a turn
  2. Write an evaluation function to return a score for a given state
  3. Search for a plan that gives the best score according to the evaluation function

For the sake of brevity, I am not going to enter into the details of writing a simulation.

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I guess you all remember pb4608 for winning the Smash the Code contest. He’s still around! He ranked 3rd in Fantastic Bits.

pb4608 postmortem

“Evaluation functions sometimes feel like magic…”

(during the contest)

“Why doesn’t this work, it’s the smartest code I have ever written!”

[…]

(2 hours before the end of the contest)

“Oh well… let’s push that code from 3 days ago. Everything I have written since then has failed”

[…]

(Fantastic Bits is finished)

Finally. Now I have some time to reflect and think about everything that I have tried during eight days.

[…]

(It’s been a week now)

In hindsight, I still can’t figure what made that code better than other versions.

[…]

Oh, I should write a post-mortem? Well, time to tell everyone how – even to me -, this code feels like magic.

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Thank you all for taking the time to share your strategies to the whole community. See you in February for Ghost in the Cell contest.

Play Fantastic Bits now