Advent of Code Solutions
advent-of-code
aoc
2015: Day 6
+119
+1
2015/06/part1-tests/input1
+1
2015/06/part1-tests/input1
···
1
+
turn on 0,0 through 999,999
+1
2015/06/part1-tests/input2
+1
2015/06/part1-tests/input2
···
1
+
toggle 0,0 through 999,0
+2
2015/06/part1-tests/input4
+2
2015/06/part1-tests/input4
+1
2015/06/part1-tests/input5
+1
2015/06/part1-tests/input5
···
1
+
turn off 499,499 through 500,500
+1
2015/06/part2-tests/input1
+1
2015/06/part2-tests/input1
···
1
+
turn on 0,0 through 0,0
+1
2015/06/part2-tests/input2
+1
2015/06/part2-tests/input2
···
1
+
toggle 0,0 through 999,999
+103
2015/06/solution.erl
+103
2015/06/solution.erl
···
1
+
#!/usr/bin/env escript
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+
% --- Part 1 Code
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+
part1(Input) -> io:format("Part 1: ~b~n", [count_lit_lights(Input, #{})]).
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+
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+
generate_coordinates({XStart, YStart}, {XEnd, YEnd}) ->
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[{X, Y} || X <- lists:seq(XStart, XEnd), Y <- lists:seq(YStart, YEnd)].
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+
8
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generate_map(Coords, Value) -> maps:from_list([{Coord, Value} || Coord <- Coords]).
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+
10
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perform_instruction(toggle, Coords, Map) ->
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maps:merge_with(
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fun(_, Current, _) ->
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case Current of
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0 -> 1;
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1 -> 0
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+
end
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end,
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Map,
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generate_map(Coords, 1)
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);
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perform_instruction(Action, Coords, Map) ->
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maps:merge(
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Map,
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case Action of
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on -> generate_map(Coords, 1);
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off -> generate_map(Coords, 0)
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end
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).
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+
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count_lit_lights([], Map) ->
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maps:fold(fun(_, Value, Accumulator) -> Accumulator + Value end, 0, Map);
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count_lit_lights([{Action, Start, End} | Instructions], Map) ->
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+
count_lit_lights(
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Instructions,
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perform_instruction(Action, generate_coordinates(Start, End), Map)
36
+
).
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+
38
+
% --- Part 2 Code
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part2(Input) -> io:format("Part 2: ~b~n", [calculate_brightness(Input, #{})]).
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+
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perform_instruction2(off, Coords, Map) ->
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maps:merge_with(
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fun(_, Current, _) ->
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case Current of
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Current when Current > 0 -> Current - 1;
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Current -> 0
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+
end
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+
end,
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Map,
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+
generate_map(Coords, 0)
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);
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perform_instruction2(Action, Coords, Map) ->
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maps:merge_with(
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+
fun(_, Current, New) -> Current + New end,
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Map,
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+
case Action of
57
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toggle -> generate_map(Coords, 2);
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on -> generate_map(Coords, 1)
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+
end
60
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).
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+
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calculate_brightness([], Map) ->
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maps:fold(fun(_, Value, Accumulator) -> Accumulator + Value end, 0, Map);
64
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calculate_brightness([{Action, Start, End} | Instructions], Map) ->
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+
calculate_brightness(
66
+
Instructions,
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perform_instruction2(Action, generate_coordinates(Start, End), Map)
68
+
).
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+
70
+
% --- Read Input
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split_coordinate(Coordinate) ->
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[X, Y] = string:split(Coordinate, ","),
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+
{Xint, _} = string:to_integer(X),
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{Yint, _} = string:to_integer(Y),
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+
{Xint, Yint}.
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+
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parse_line(Data) ->
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case string:split(string:trim(Data), " ", all) of
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["toggle", Start, _, End] -> {toggle, split_coordinate(Start), split_coordinate(End)};
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["turn", "on", Start, _, End] -> {on, split_coordinate(Start), split_coordinate(End)};
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["turn", "off", Start, _, End] -> {off, split_coordinate(Start), split_coordinate(End)}
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end.
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+
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read_input() -> read_input("").
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read_input(Prev) ->
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case io:get_line("") of
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eof -> Prev;
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{error, _} -> halt(1);
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Data when Prev == "" -> read_input([parse_line(Data)]);
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Data -> read_input(Prev ++ [parse_line(Data)])
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end.
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+
93
+
main(Args) ->
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Input = read_input(),
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+
case Args of
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["1"] ->
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+
part1(Input);
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+
["2"] ->
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+
part2(Input);
100
+
_ ->
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+
part1(Input),
102
+
part2(Input)
103
+
end.