Advent of Code 2022 - Day 1 Discussions

Questions & Discussions Coding Challenges
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This topic is about Day 1 of the Advent of Code 2022.

With less than 2 hours to go for Advent of Code 2022, I am leaving this post open so that folks can discuss their day 1 adventures when it begins (12:00 AM EST)!

Link to our leaderboard:

https://adventofcode.com/2022/leaderboard/private/view/370884

The entry code is:
370884-a6a71927

Good luck!

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My solution:

main(File) ->
    {ok, RawData} = file:read_file(File),
    Data = [ [binary_to_integer(X) || X <- binary:split(N, <<"\n">>, [global, trim])]
             || N <- binary:split(RawData, <<"\n\n">>, [global, trim]) ],
    io:format("part 1: ~p~n", [solve1(Data)]),
    io:format("part 2: ~p~n", [solve2(Data)]).

solve1(Data) ->
    lists:max([ lists:sum(X) || X <- Data ]).

solve2(Data) ->
    lists:sum(lists:sublist(lists:reverse(lists:sort([ lists:sum(X) || X <- Data ])), 3)).
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I used :gb_sets to get top 3. It doesn’t help much since it is O(n.lg(n)) vs O(lg(n)) and n here is not large. But felt like let’s just try this :smiley: (Elixir though)

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Hi the links are still 2021 you should change them to 2022

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Thank you!

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I also used a series of split, map, sum and max from the lists module.
As I did not read the requirements to the end, I also implemented the calculation of which elf carried the most calories (= index of max in the list of sums).
It seems that the lists module does not provide such a function

find(Elem :: term(), List :: list()) -> Index :: integer() | enoent.

find(Elem, List) ->
    find(Elem, List, 1).
find(Elem, [], Idx) ->
    enoent;
find(Elem, [Elem|_List], Idx) ->
    Idx;
find(Elem, [_|List], Idx) ->
    find(Elem, List, Idx + 1).

or did I not look close enough?

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Yes, looks like there is not Enum.find_index equivalent in lists module. However, can anyone explain why string:str(List, [Elem]) - 1 yields the desired index?

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I started doing Erlang solution. I am not used to Erlang so might look funny my code. Here’s Day 1:

-module(day_1).

-export([solve/0]).

input() ->
    {ok, RawCalories} = file:read_file("data/1.txt"),
    RawCalories.

solve() ->
    RawCalories = input(),
    ParsedData = parse(RawCalories),
    Calories = [lists:sum(X) || X <- ParsedData],
    Solve1 = solve1(Calories),
    Solve2 = solve2(Calories),

    {Solve1, Solve2}.

solve1(Calories) -> lists:max(Calories).

solve2(Calories) ->
    SortedCalories =
        lists:reverse(
            lists:sort(Calories)),
    Top3 = lists:sublist(SortedCalories, 3),
    lists:sum(Top3).

parse(RawCalories) ->
    [[binary_to_integer(Calory) || Calory <- ElfCalories]
     || ElfCalories
            <- [binary:split(ElfCalories, <<"\n">>, [global, trim])
                || ElfCalories
                       <- [Calories
                           || Calories <- binary:split(RawCalories, <<"\n\n">>, [global, trim])]]].
2 Likes