Synacor Challenge

https://challenge.synacor.com/

EDIT: So there's two news. The bad news is, that the original website no longer works! The good news is, that there is this repo: https://github.com/Aneurysm9/vm_challenge hosting not only one of the versions of the binary file, but also providing MD5 checksums of the codes. So, you can still the the challenge, enjoy!

JavaScript Implementation, browser+node

The fun is real, take the challenge!

Spoilers below this line

Reading the binary

• See read.js.

Building VM

• Self-navigating TDD.
• Simple stuff, watch for the incidental fuzziness in arch-spec regarding mainly the rmem and wmem instructions.
• see Computer.js.

Twisty little mazes, all alike

• Built UI for playing the text game. Deployed here.
• Solved the Grue-heavy part manually by moving through the dungeon, realizing that it occupies some non-Euclidean space (A -> south -> B -> north -> !A).

Ruins

• Permutation of 5 numbers fitting the equation.
• See solveRuins in script.js.

Teleporter

• Built the transpiler to asm, see challenge.asm.
• Hacked the teleporter to get a code rejected by the website, ouch.
• By stack-tracing found the problematic method. Spent some number of hours, interrupted, trying to simulate/optimize it. Got to an ugly method that produced a solution after some hours.
• Later, found out about https://en.wikipedia.org/wiki/Ackermann_function and produced a proper solver.
• By far the most difficult part of the challenge.
• See teleporter.js.

Beach

• Manually traced down the map.
• Built a simple recursive solver - BFS graph traverse.
• See beach.js.

Overall great stuff, really enjoyed it!