89 lines
2.3 KiB
Erlang
89 lines
2.3 KiB
Erlang
%% to compile: erlc day3A.erl
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%% to run: erl -noshell -s day5 solve
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%%
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-module(day13).
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-export ([solve/0, solve/1, solve/2]).
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-export ([read_input/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_input()).
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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_input() ->
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{ok, IO} = file:open("input.txt", 'read'),
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Data = read_input(IO),
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file:close(IO),
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Data.
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read_input(IO) ->
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read_input(IO, []).
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read_input(IO, Input) ->
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case read_line(IO) of
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'eof' -> Input;
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Line -> read_input(IO, Input ++ [Line])
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end.
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read_line(IO) ->
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case file:read_line(IO) of
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'eof' -> 'eof';
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{ok, Line} -> parse_line(Line)
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end.
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parse_line(Line) ->
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Points = string:tokens(Line, " ,\n"),
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[X, Y] = [list_to_integer(X) || X <- Points],
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{X, Y}.
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solution1(Input) ->
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io:format("Input ~p~n", [Input]),
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F1 = fold(x, 655, Input),
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length(F1).
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solution2(Input) ->
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I = fold(y,6,fold(y,13,fold(y,27,fold(x,40,fold(y,55,fold(x,81,fold(y,111,fold(x,163,fold(y,223,fold(x,327,fold(y,447,fold(x,655, Input)))))))))))),
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MaxX = lists:foldl(fun({T, _}, Acc) -> case T > Acc of 'true' -> T; _ -> Acc end end, 0, I),
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MaxY = lists:foldl(fun({_, T}, Acc) -> case T > Acc of 'true' -> T; _ -> Acc end end, 0, I),
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Coords = [{X,Y} || Y <- lists:seq(0,MaxY), X <- lists:seq(0,MaxX)],
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output(Coords, I, MaxX).
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output([], I, MaxX) -> ok;
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output([{X,Y}|Rest], I, MaxX) ->
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case lists:member({X,Y}, I) of
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'true' -> io:format("#");
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'false' -> io:format(" ")
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end,
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case X == MaxX of
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'true' -> io:format("~n");
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'false' -> ok
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end,
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output(Rest, I, MaxX).
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fold(y, N, Input) ->
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L1 = [ {X, (Y * -1) + N} || {X, Y} <- Input],
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{Sat, NotSat} = lists:partition(fun({_,Y}) -> Y < 0 end, L1),
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Sat2 = [{X, Y * -1}|| {X, Y} <- Sat],
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L2 = lists:usort(NotSat ++ Sat2),
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[ {X, (Y - N) * -1} || {X,Y} <- L2];
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fold(x, N, Input) ->
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L1 = [ {(X * -1) + N, Y} || {X, Y} <- Input],
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{Sat, NotSat} = lists:partition(fun({X,_}) -> X < 0 end, L1),
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Sat2 = [{X * -1, Y}|| {X, Y} <- Sat],
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L2 = lists:usort(NotSat ++ Sat2),
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[ {(X - N) * -1, Y} || {X,Y} <- L2].
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