Advent of Code 2021 in Datalog

AoC21 using Souffle datalog.

How to run?

Puzzles are organized by day; answer to part 1 of day 1 is in day01/day01a.dl, answer to part 2 is in day01b.dl. The datalog files have .dl extension. The input files have .facts extension.

Interpreter mode

The quickest way to run a datalog program is to execute Souffle in interpreter mode. The interpreter mode may use N threads with option souffle -j N.

cd day01
souffle -D- -F. day01a.dl
souffle -D- -F. -j 4 day01b.dl

Compiled mode

For long programs, or programs with large input, Souffle can generate c++ code.

cd day06

# compile, run on 8 threads and drop the executable
souffle -D- -F. -j 8 -c day06a

# compile and keep the executable
souffle -D- -F. -o day06a day06a.dl
# run on 4 threads
./day06a -j 4

What is going on?

By default only the answer relation is printed out and provides the answer to the puzzle.

You may want to reveal the content of any of the intermediate relation by adding the appropriate .output directive in the datalog code.

For instance add the line .output larger_than_previous in day01/day01a.dl so that the larger_than_previous relation gets printed on the standard output.