Rubot is a blazing fast Rubik's cube solver written in C. It generates a tiny ~1 MB lookup table which can be searched in nanoseconds. Solutions average 32 moves, with a guaranteed max of 46.
Rubot implements Thistletwaite's algorithm, a major breakthrough which introduced a novel approach using group theory in 1981. This algorithm was selected over later approaches such as Kociemba's algorithm and Korf's algorithm which produce even fewer moves because those methods either take more time to solve or require significantly larger lookup tables.
This project started as a final project for ECE4670: Digital Systems Design Using Microcontrollers in Fall 2021.
Build the executable ./rubot using the provided Makefile by running:
make
The first way to use ./rubot is to generate both a scramble and a solution. The number of moves in the scramble is passed to ./rubot, then the sequence of scramble and solution moves is printed to the console. For example:
./rubot 25
The second way to use ./rubot is to generate a solution for a given scramble. The sequence of scramble moves is passed to ./rubot, then the sequence of solution moves is printed to the console. Remember to escape ' on the console. For example:
./rubot B2, U2, L, D\', R\', L2, B, R, L\', U
You can also optionally pass the following flags to ./rubot to modify its behavior:
-hor--help: prints the help screen
The first time ./rubot is run it will generate a 1.05 MB database. This will take either minutes or seconds, depending on your hardware. The chart below shows how long each phase took on my Intel Core i7-13700K.
| phase | database size | database updates | states generated | time |
|---|---|---|---|---|
| 1 | 2048 | 6491 | 68464 | 0.02 s |
| 2 | 1082565 | 3319998 | 25938961 | 14.3 s |
| 3 | 352800 | 1965338 | 13069024 | 11.1 s |
| 4 | 663552 | 1766474 | 8832372 | 7.0 s |