36 lines
2.3 KiB
Erlang
36 lines
2.3 KiB
Erlang
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-module(day9).
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-export([start/0]).
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calc_group_score(String)
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-> calc_group_score(re:split(String, ""), 0, false, 0, false, 0).
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calc_group_score([<<>>], Score, _LastCharWasEx, _Depth, _FoundGarbage, CharCount)
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-> {Score, CharCount};
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calc_group_score([_Head|Tail], Score, LastCharWasEx, Depth, FoundGarbage, CharCount)
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when LastCharWasEx == true, FoundGarbage == true -> calc_group_score(Tail, Score, false, Depth, true, CharCount);
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calc_group_score([Head|Tail], Score, _LastCharWasEx, Depth, FoundGarbage, CharCount)
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when Head == <<"!">> -> calc_group_score(Tail, Score, true, Depth, FoundGarbage, CharCount);
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calc_group_score([Head|Tail], Score, _LastCharWasEx, Depth, FoundGarbage, CharCount)
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when Head == <<"{">>, FoundGarbage == false -> calc_group_score(Tail, Score, false, Depth + 1, false, CharCount);
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calc_group_score([Head|Tail], Score, _LastCharWasEx, Depth, FoundGarbage, CharCount)
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when Head == <<"}">>, FoundGarbage == false -> calc_group_score(Tail, Score + Depth, false, Depth - 1, false, CharCount);
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calc_group_score([Head|Tail], Score, _LastCharWasEx, Depth, FoundGarbage, CharCount)
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when Head == <<"<">>, FoundGarbage == false -> calc_group_score(Tail, Score, false, Depth, true, CharCount);
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calc_group_score([Head|Tail], Score, _LastCharWasEx, Depth, _FoundGarbage, CharCount)
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when Head == <<">">> -> calc_group_score(Tail, Score, false, Depth, false, CharCount);
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calc_group_score([_Head|Tail], Score, _LastCharWasEx, Depth, FoundGarbage, CharCount)
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when FoundGarbage == true -> calc_group_score(Tail, Score, false, Depth, FoundGarbage, CharCount + 1);
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calc_group_score([_Head|Tail], Score, _LastCharWasEx, Depth, FoundGarbage, CharCount)
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-> calc_group_score(Tail, Score, false, Depth, FoundGarbage, CharCount).
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start()
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-> io:fwrite("~p~n", [calc_group_score("{}")]),
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io:fwrite("~p~n", [calc_group_score("{{{}}}")]),
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io:fwrite("~p~n", [calc_group_score("{{},{}}")]),
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io:fwrite("~p~n", [calc_group_score("{{{},{},{{}}}}")]),
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io:fwrite("~p~n", [calc_group_score("{<a>,<a>,<a>,<a>}")]),
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io:fwrite("~p~n", [calc_group_score("{{<ab>},{<ab>},{<ab>},{<ab>}}")]),
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io:fwrite("~p~n", [calc_group_score("{{<!!>},{<!!>},{<!!>},{<!!>}}")]),
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io:fwrite("~p~n", [calc_group_score("{{<a!>},{<a!>},{<a!>},{<ab>}}")]),
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{ok, File} = file:read_file("input"),
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io:fwrite("~p~n", [calc_group_score(unicode:characters_to_list(File))]).
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