Advent of Code 2020 Day 1/25 in the Raku programming language

OK, I solved a few days of the on-going this year’s Advent of Code, so maybe it is a good idea to document it a bit so that those who like Raku can look at it too.

So, the problem of Day 1 is to take a long list of integers and find such two neighbouring numbers that add to to 2020. The second part of the task is to find three such numbers.

I saved a list of integers in a separate text file (it is also the case for all further tasks), so I use Raku to read the data from it. Then, we can use the combinations method, which is built-in in Raku and is doing exactly what we need for this task: it takes a list and returns all combinations of 2 or 3 elements:

my @data = 'data.txt'.IO.lines;
say [*] @data.combinations(2).first(*.sum == 2020);
say [*] @data.combinations(3).first(*.sum == 2020);

And that’s it for this day 🙂

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→ Browse the code on GitHub
→ See all blog posts on Advent of Code 2020