111 lines
3.0 KiB
Erlang
111 lines
3.0 KiB
Erlang
%% to compile: erlc day3A.erl
|
|
%% to run: erl -noshell -s day5 solve
|
|
%%
|
|
-module(day5).
|
|
|
|
-export ([solve/0, solve/1, solve/2]).
|
|
-export ([read_input/0]).
|
|
|
|
solve() ->
|
|
solve(['1']),
|
|
solve(['2']),
|
|
init:stop().
|
|
|
|
solve(A) ->
|
|
solve(A, read_input()).
|
|
|
|
solve(['1'], D) ->
|
|
io:format("The solution to ~p puzzle1 is: ~p~n", [?MODULE, solve(1, D)]);
|
|
solve(1, D) ->
|
|
solution1(D);
|
|
solve(['2'], D) ->
|
|
io:format("The solution to ~p puzzle2 is: ~p~n", [?MODULE, solve(2, D)]);
|
|
solve(2, D) ->
|
|
solution2(D).
|
|
|
|
read_input() ->
|
|
{ok, IO} = file:open("input.txt", 'read'),
|
|
Data = read_input(IO),
|
|
file:close(IO),
|
|
Data.
|
|
|
|
read_input(IO) ->
|
|
read_input(IO, []).
|
|
|
|
read_input(IO, Input) ->
|
|
case read_line(IO) of
|
|
'eof' ->
|
|
lists:map(fun([{X1,Y1},{X2,Y2}]) ->
|
|
case X1 > X2 orelse (X1 == X2 andalso Y1 > Y2) of
|
|
'true' -> [{X2,Y2},{X1,Y1}];
|
|
'false' -> [{X1,Y1},{X2,Y2}]
|
|
end
|
|
end, Input);
|
|
Line -> read_input(IO, Input ++ [Line])
|
|
end.
|
|
|
|
read_line(IO) ->
|
|
case file:read_line(IO) of
|
|
'eof' -> 'eof';
|
|
{ok, Line} -> parse_line(Line)
|
|
end.
|
|
|
|
parse_line(Line) ->
|
|
Points = string:tokens(Line, " ,->\n"),
|
|
[X1, Y1, X2, Y2] = [list_to_integer(X) || X <- Points],
|
|
[{X1, Y1},{X2,Y2}].
|
|
|
|
solution1(Input) ->
|
|
HV = get_hor_vert(Input),
|
|
Points = lists:sort(
|
|
lists:flatten(
|
|
[[{X,Y} || X <- lists:seq(X1, X2, case X1 =< X2 of 'true' -> 1; _ -> -1 end),
|
|
Y <- lists:seq(Y1, Y2, case Y1 =< Y2 of 'true' -> 1; _ -> -1 end)] || [{X1,Y1},{X2,Y2}] <- HV]
|
|
)
|
|
),
|
|
Count = count_duplicates(Points),
|
|
Count.
|
|
|
|
solution2(Input) ->
|
|
Points = get_all_points(Input),
|
|
Count = count_duplicates(lists:sort(Points)),
|
|
Count.
|
|
|
|
|
|
get_hor_vert(Input) ->
|
|
lists:filter(fun([{X1, Y1},{X2,Y2}]) -> X1 == X2 orelse Y1 == Y2 end, Input).
|
|
|
|
get_all_points(Input) ->
|
|
get_all_points(Input, []).
|
|
|
|
get_all_points([], Acc) ->
|
|
Acc;
|
|
get_all_points([[{X1,Y1},{X2,Y2}]|Rest], Acc) when X1 == X2 ->
|
|
get_all_points(Rest, Acc ++ [{X1, Y} || Y <- lists:seq(Y1,Y2)]);
|
|
get_all_points([[{X1,Y1},{X2,Y2}]|Rest], Acc) when Y1 == Y2 ->
|
|
get_all_points(Rest, Acc ++ [{X, Y1} || X <- lists:seq(X1,X2)]);
|
|
get_all_points([[{X1,Y1},{X2,Y2}]|Rest], Acc) when Y1 < Y2 ->
|
|
get_all_points(Rest, Acc ++ [{X, Y1-X1+X} || X <- lists:seq(X1,X2)]);
|
|
get_all_points([[{X1,Y1},{X2,Y2}]|Rest], Acc) when Y1 > Y2 ->
|
|
get_all_points(Rest, Acc ++ [{X, (-1 * X) + X1 + Y1 } || X <- lists:seq(X1,X2)]).
|
|
|
|
count_duplicates(Points) ->
|
|
count_duplicates(Points, []).
|
|
|
|
count_duplicates([], Count) ->
|
|
lists:foldl(fun({X, _P}, Acc) ->
|
|
case X > 1 of 'true' -> Acc + 1; _ -> Acc end end, 0, Count);
|
|
count_duplicates([H|T], Count) ->
|
|
case T /= [] andalso hd(T) == H of
|
|
'true' -> count_duplicate(H, T, Count, 1);
|
|
_Else -> count_duplicates(T, Count ++ [{1, H}])
|
|
end.
|
|
|
|
count_duplicate(H, [H|T], Count, X) ->
|
|
count_duplicate(H, T, Count, X + 1);
|
|
count_duplicate(H, List, Count, X) ->
|
|
count_duplicates(List, Count ++ [{X, H}]).
|
|
|
|
|
|
|