Advent of Code 2024 Day 1 Part 1 and Part 2

aoc_1.erl

-module(aoc).

-export([main/1]).

-import(file, [read_file/1]).
-import(lists, [unzip/1, map/2, zip/2, sort/1, foldl/3, filter/2, sum/1]).
-import(maps, [get/3, update_with/4]).
-import(string, [is_empty/1, split/3, trim/1]).

main([Path]) ->
  {ok, String} = read_file(Path),
  {A, B} = unzip(map(fun line_elements/1, split(String, "\n", all))),
  io:format("Sum: ~p~n", [sum_diffs(zip(sort(A), sort(B)))]),
  io:format("SimScore: ~p~n", [compute_sim_score(make_counts_map(B), A)]),
  erlang:halt(0).

line_elements(Line) when is_binary(Line) ->
  list_to_tuple(filter(fun(S) -> not is_empty(S) end, split(trim(Line), " ", all))).

sum_diffs(L) when is_list(L) ->
  sum(map(fun({A, B}) -> abs(binary_to_integer(A) - binary_to_integer(B)) end, L)).

make_counts_map(L) when is_list(L) ->
  foldl(fun(K, M) -> update_with(K, fun(V) -> V + 1 end, 1, M) end, #{}, L).

compute_sim_score(M, L) when is_map(M) and is_list(L) ->
  foldl(fun(X, S) -> S + get(X, M, 0) * binary_to_integer(X) end, 0, L).