101 lines
2.6 KiB
Erlang
101 lines
2.6 KiB
Erlang
%% to compile: erlc day3A.erl
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%% to run: erl -noshell -s day3 solve
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%%
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-module(day4).
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-export ([solve/0, solve/1, solve/2]).
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-export ([read_boards/0]).
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solve() ->
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solve(['1']),
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solve(['2']),
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init:stop().
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solve(A) ->
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solve(A, read_boards()).
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solve(['1'], D) ->
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io:format("The solution to ~p puzzle1 is: ~p~n", [?MODULE, solve(1, D)]);
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solve(1, D) ->
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solution1(D);
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solve(['2'], D) ->
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io:format("The solution to ~p puzzle2 is: ~p~n", [?MODULE, solve(2, D)]);
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solve(2, D) ->
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solution2(D).
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read_boards() ->
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{ok, IO} = file:open("boards.txt", 'read'),
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Data = read_boards(IO),
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file:close(IO),
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Data.
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read_boards(IO) ->
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read_boards(IO, []).
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read_boards('eof', Boards) ->
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Boards;
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read_boards(IO, Boards) ->
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case read_board(IO) of
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'eof' -> Boards;
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Board -> read_boards(IO, Boards ++ [Board])
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end.
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read_board(IO) ->
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read_line(IO, []).
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read_line(IO, Board) ->
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case file:read_line(IO) of
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{ok, "\n"} -> make_board(Board);
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'eof' -> 'eof';
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{ok, Line} -> read_line(IO, [[ list_to_integer(X) || X <- string:tokens(Line, " \n")]|Board])
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end.
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make_board(B) ->
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B ++ [lists:map(fun(X) -> lists:nth(Y,X) end, B) || Y <- lists:seq(1,5)].
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solution1(Boards) ->
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Input = get_input(),
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Bingo = process(Boards, 1, Input),
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score(Bingo).
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solution2(Boards) ->
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Input = get_input(),
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Bingo = process(Boards, length(Boards), Input),
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score(Bingo).
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score({'bingo', Num, Board}) ->
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Fun = fun(L) -> lists:foldl(fun(X, Acc) -> X + Acc end, 0, L) end,
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Num * (Fun([Fun(X) || X <- Board]) / 2).
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process(Boards, _Count, []) -> Boards;
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process(Boards, Count, [H|T]) ->
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New_boards = process_boards(Boards, H, []),
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case is_bingo(New_boards) of
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{'bingo', Board} when Count == 1 -> {'bingo', H, Board};
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{'bingo', _Board} ->
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New_boards2 = delete_bingo_boards(New_boards),
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process(New_boards2, Count - length(New_boards) + length(New_boards2), T);
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_Else -> process(New_boards, Count, T)
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end.
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process_boards([], _Num, Acc) ->
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Acc;
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process_boards([B|T], Num, Acc) ->
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process_boards(T, Num, [[lists:delete(Num, X) || X <- B]|Acc]).
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is_bingo([]) -> 'false';
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is_bingo([Board|Rest]) ->
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case is_line(Board) of
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'true' -> {'bingo', Board};
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'false' -> is_bingo(Rest)
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end.
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is_line(Board) ->
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lists:any(fun(X) -> X == [] end, Board).
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delete_bingo_boards(Boards) ->
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[Board || Board <- Boards, not is_line(Board)].
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get_input() ->
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[83,69,34,46,30,23,19,75,22,37,89,78,32,39,11,44,95,43,26,48,84,53,94,88,18,40,62,35,27,42,15,2,91,20,4,64,99,71,54,97,52,36,28,7,74,45,70,86,98,1,61,50,68,6,77,8,57,47,51,72,65,3,49,24,79,13,17,92,41,80,63,67,82,90,55,0,10,93,38,21,59,73,33,31,9,76,5,66,16,58,85,87,12,29,25,14,96,56,60,81].
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