47 lines
1.2 KiB
Mathematica
47 lines
1.2 KiB
Mathematica
:- module day1.
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:- interface.
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:- import_module basics.
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:- import_module io.
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:- import_module list.
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:- pred run(part::in, list(string)::in, io::di, io::uo) is det.
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:- implementation.
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:- import_module die.
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:- import_module std_util.
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:- import_module string.
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:- import_module int.
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run(Part, Args, !IO) :-
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if Args = [File] then (
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read_named_file_as_lines(File, LinesM, !IO),
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need(LinesM, Lines),
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Totals = go(Lines),
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( Part = one,
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format("%d\n", [i(det_head(Totals))], !IO)
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; Part = two,
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Res = sum(take_upto(3, Totals)),
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format("%d\n", [i(Res)], !IO)
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)
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) else die("expected one readable file").
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:- func go(list(string)) = list(int).
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go(Lines) = sort(converse(ordering), map(int_sum, gather(Lines))).
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:- func gather(list(string)::in) = (list(list(string))::out(non_empty_list)).
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gather([]) = [[]].
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gather([X | Xs]) = Groups :-
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[Ys | Yss] = gather(Xs),
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(if X = "" then Groups = [[], Ys | Yss]
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else Groups = [[X | Ys] | Yss]).
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:- func sum(list(int)) = int.
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sum(Xs) = foldl(func(X, Y) = X + Y, Xs, 0).
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:- func int_sum(list(string)) = int.
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int_sum(Xs) = sum(map(det_to_int, Xs)).
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:- pred need(io.res(T)::in, T::out) is det.
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need(ok(X), X).
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need(error(E), _) :- die(error_message(E)).
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