Day 3 - Advent of Code 2023
Mix.install([:kino, :benchee])Links
Input
input = Kino.Input.textarea("Please paste your input file:")input = input |> Kino.Input.read()
# input = AdventOfCode.Input.get!(3, 2023)"........440...............418..643.....438......740.261......................................727...........................870..............\n...............338.............-........*.......*.......34&.$........@.....&742................................353..26.......*...188...238..\n..................*369.....334.......624..749....533........690...894...........466......../....&......294....................1.............\n..338....367............................................../...............565..@....456.357....873........#..=...916.#60....................\n........*...............*......402.......473..%400..+415.165....364........*.....$....*......*...............410...=..........#........#....\n..342....886....122..457..866........438....*.....................*........739...716...131....561..748.......................206......155...\n.................-.........../..........@.185..78.556........120..856..436............................*.....%730.307....382#................\n...................352...........................*....282.......$...........*......716......904*588....807.........*........................\n.590.......225....*......610...............&434......*...................805.878......*......................#539..412......452......993....\n....*407...................%............=..........489..............#..................390....621.708........................-..............\n..........542#...880...@.......*.....%...877..................264....3........750.............../.*.............-.......570.......&.........\n.....290...........@.540....167.873.970................669.....#.....................169...........718....&...240......*........764.400.....\n.......*......639.......................103.....@.......*..................................731.........413...........974...............*....\n......174........#..-331....&................465.............428...$118.....................*......714.......209*418........*....@......513.\n...........869.............120.....101................379...*..................488.579...344......*.......................94.802.105........\n...834.............254............=........657.........@...198..160....258........*.............449........972@.553%.................234....\n...*.....@...........*....................../.....273............*...................&......................................545.365.........\n.773......296.........85...256.......977.............*....203...216.....394......872.240.......406*.......&254...............*..*...........\n......-...............................................830.....%....................*..............................................615.608...\n...739..15*903....93.........714..442*...769.....838.......829.....741.....@469.......60...........181..376.......63.........172........*...\n.................=......306............@...*.......*...900.....309..*...............-.....428..333...*.....*921..*....673............499....\n.........599...........&........221....137..432....930....*.....*..216..........#..381...*.....*....767.................@..........=........\n.993......-..............243....$.......................150...456.............677......400..338.............................766.468.........\n........................*....................509....................815.............................................308.....*..........575..\n...................908.112........767....215..........400..220........*............962.825......46......30.....21-........875......453*.....\n....845........840............../....*.../........423*....*....929..76......682-...*.....&.........@.....*..........&196....................\n867.*.........+.........=671....429..278......46.......$...194../.................611.............401.....788....&.......201.........*38....\n....21...599........................................863..................946...23............*547.............244...........*.....963.......\n.........*...........65.............659......612..........497.......&705..................121.........................29....80..............\n......." <> ...
Solution
defmodule Day03 do
defdelegate parse(input), to: __MODULE__.Input
def part1(input) do
{numbers, grid} = parse(input)
numbers
|> Enum.filter(fn digits ->
Enum.any?(digits, fn {{row, col}, _} ->
[
{row - 1, col - 1},
{row - 1, col},
{row - 1, col + 1},
{row, col - 1},
{row, col + 1},
{row + 1, col - 1},
{row + 1, col},
{row + 1, col + 1}
]
|> Enum.any?(fn xy ->
case grid[xy] do
?. -> false
nil -> false
v when v in ?0..?9 -> false
_ -> true
end
end)
end)
end)
|> Enum.map(&digits_to_integer/1)
|> Enum.sum()
end
def part2(input) do
{numbers, grid} = parse(input)
grid
|> Enum.filter(fn {_, v} -> v == ?* end)
|> Enum.map(fn {{row, col}, _} ->
numbers
|> Enum.filter(fn number ->
Enum.any?(number, fn {{r, c}, _} ->
abs(row - r) <= 1 and abs(col - c) <= 1
end)
end)
end)
|> Enum.filter(&(length(&1) == 2))
|> Enum.map(fn gear ->
Enum.map(gear, &digits_to_integer/1)
end)
|> Enum.map(&Enum.product/1)
|> Enum.sum()
end
defp digits_to_integer(digits) do
digits
|> Enum.map(fn {_, digit} -> digit end)
|> to_string()
|> String.to_integer()
end
defmodule Input do
def parse(input) when is_binary(input) do
input
|> String.splitter("\n", trim: true)
|> parse()
end
def parse(input) do
rows =
input
|> Enum.with_index()
|> Enum.map(&parse_line/1)
is_digit? = fn {_, x} -> x in ?0..?9 end
numbers =
Enum.flat_map(rows, fn row ->
row
|> Enum.chunk_by(is_digit?)
|> Enum.filter(fn [h | _] -> is_digit?.(h) end)
end)
grid = rows |> List.flatten() |> Enum.into(%{})
{numbers, grid}
end
def parse_line({line, row}) do
line
|> String.to_charlist()
|> Enum.with_index()
|> Enum.map(fn {g, col} ->
{{row, col}, g}
end)
end
end
end{:module, Day03, <<70, 79, 82, 49, 0, 0, 19, ...>>,
{:module, Day03.Input, <<70, 79, 82, ...>>, {:parse_line, 1}}}
What is the sum of all of the part numbers in the engine schematic?
Your puzzle answer was 532331.
Day03.part1(input)532331
What is the sum of all of the gear ratios in your engine schematic?
Your puzzle answer was 82301120.
Day03.part2(input)82301120
Both parts of this puzzle are complete! They provide two gold stars: **
At this point, you should return to your Advent calendar and try another puzzle.
If you still want to see it, you can get your puzzle input.
Tests
ExUnit.start(auto_run: false)
defmodule Day03Test do
use ExUnit.Case, async: false
setup_all do
[
input:
"467..114..\n...*......\n..35..633.\n......#...\n617*......\n.....+.58.\n..592.....\n......755.\n...$.*....\n.664.598.."
]
end
describe "part1/1" do
test "returns expected value", %{input: input} do
assert Day03.part1(input) == 4361
end
end
describe "part2/1" do
test "returns expected value", %{input: input} do
assert Day03.part2(input) == 467_835
end
end
end
ExUnit.run()..
Finished in 0.00 seconds (0.00s async, 0.00s sync)
2 tests, 0 failures
Randomized with seed 458078
%{total: 2, failures: 0, excluded: 0, skipped: 0}
Benchmarking
# https://github.com/bencheeorg/benchee
Benchee.run(
%{
"Part 1" => fn -> Day03.part1(input) end,
"Part 2" => fn -> Day03.part2(input) end
},
memory_time: 2,
reduction_time: 2
)
nilWarning: the benchmark Part 1 is using an evaluated function.
Evaluated functions perform slower than compiled functions.
You can move the Benchee caller to a function in a module and invoke `Mod.fun()` instead.
Alternatively, you can move the benchmark into a benchmark.exs file and run mix run benchmark.exs
Warning: the benchmark Part 2 is using an evaluated function.
Evaluated functions perform slower than compiled functions.
You can move the Benchee caller to a function in a module and invoke `Mod.fun()` instead.
Alternatively, you can move the benchmark into a benchmark.exs file and run mix run benchmark.exs
Operating System: macOS
CPU Information: Apple M1
Number of Available Cores: 8
Available memory: 8 GB
Elixir 1.15.7
Erlang 26.1.1
Benchmark suite executing with the following configuration:
warmup: 2 s
time: 5 s
memory time: 2 s
reduction time: 2 s
parallel: 1
inputs: none specified
Estimated total run time: 22 s
Benchmarking Part 1 ...
Benchmarking Part 2 ...
Name ips average deviation median 99th %
Part 1 191.67 5.22 ms ±4.48% 5.14 ms 5.77 ms
Part 2 47.29 21.15 ms ±1.31% 21.05 ms 21.78 ms
Comparison:
Part 1 191.67
Part 2 47.29 - 4.05x slower +15.93 ms
Memory usage statistics:
Name Memory usage
Part 1 6.18 MB
Part 2 30.61 MB - 4.96x memory usage +24.43 MB
**All measurements for memory usage were the same**
Reduction count statistics:
Name average deviation median 99th %
Part 1 0.51 M ±0.02% 0.51 M 0.51 M
Part 2 6.83 M ±0.01% 6.83 M 6.84 M
Comparison:
Part 1 0.51 M
Part 2 6.83 M - 13.36x reduction count +6.32 M
nil
