using Test

data = open("input") do f
    split(read(f, String))
end

priority(x) = islowercase(x) ? x - 'a' + 1 : x - 'A' + 27

@testset "solutions" begin
    @test map(
        s -> intersect(s[1:length(s)÷2], s[length(s)÷2+1:end])[1] |> priority,
        data,
    ) |> sum == 8072
    @test [intersect(data[i:i+2]...)[1] for i ∈ 1:3:length(data)] .|> priority |> sum == 2567
end