Day 12
Mix.install([
{:kino, "~> 0.7.0"}
])
IEx.Helpers.c("/Users/johnb/dev/2023adventOfCode/advent_of_code.ex")
alias AdventOfCode, as: AOC
alias Kino.Input
# Note: when making the next template, something like this works well:
# `cat day04.livemd | sed 's/03/04/' > day04.livemd`
#
Installation and Data
input_p1example = Kino.Input.textarea("Example Data")
input_p1puzzleInput = Kino.Input.textarea("Puzzle Input")
input_source_select =
Kino.Input.select("Source", [{:example, "example"}, {:puzzle_input, "puzzle input"}])
p1data = fn ->
(Kino.Input.read(input_source_select) == :example &&
Kino.Input.read(input_p1example)) ||
Kino.Input.read(input_p1puzzleInput)
end
Part 1
defmodule Day12 do
def damaged_run_lengths(record) do
record
|> String.split(~r/[^#]/, trim: true)
|> Enum.map(&String.length/1)
end
def matching_permutations(required_run_lengths, chars, prev_chars \\ "")
def matching_permutations(required_run_lengths, [char], prev_chars) do
if char == "?" do
if damaged_run_lengths(prev_chars <> ".") == required_run_lengths ||
damaged_run_lengths(prev_chars <> "#") == required_run_lengths do
# IO.puts("match? '#{prev_chars <> "."}' or '#{prev_chars <> "#"}'")
1
else
0
end
else
if damaged_run_lengths(prev_chars <> char) == required_run_lengths do
# IO.puts("match: #{prev_chars <> char}")
1
else
0
end
end
end
def matching_permutations(required_run_lengths, [char | rest], prev_chars) do
case char do
"?" ->
matching_permutations(required_run_lengths, rest, prev_chars <> ".") +
matching_permutations(required_run_lengths, rest, prev_chars <> "#")
_ ->
matching_permutations(required_run_lengths, rest, prev_chars <> char)
end
end
def solve(text) do
text
|> AOC.as_single_lines()
|> Enum.map(fn line ->
[record, required_run_lengths] = String.split(line, " ", trim: true)
# |> IO.inspect()
required_run_lengths =
required_run_lengths
|> String.split(",", trim: true)
|> Enum.map(fn digits -> digits |> String.to_integer() end)
# |> IO.inspect(label: "'#{record}' .vs #{inspect(damaged_run_lengths(record))}")
chars = String.split(record, "", trim: true)
matching_permutations(required_run_lengths, chars)
|> IO.inspect(label: "matching_permutations")
end)
|> Enum.sum()
end
def solve2(text) do
text
|> AOC.as_single_lines()
|> Enum.map(fn line ->
[record, required_run_lengths] = String.split(line, " ", trim: true)
# |> IO.inspect()
run_lengths =
required_run_lengths
|> String.split(",", trim: true)
|> Enum.map(fn digits -> digits |> String.to_integer() end)
# |> IO.inspect(label: "'#{record}' .vs #{inspect(damaged_run_lengths(record))}")
record = Enum.join([record, record, record, record, record], "?")
required_run_lengths =
run_lengths ++ run_lengths ++ run_lengths ++ run_lengths ++ run_lengths
IO.puts(record)
IO.inspect(required_run_lengths)
chars = String.split(record, "", trim: true)
matching_permutations(required_run_lengths, chars)
|> IO.inspect(label: "matching_permutations")
end)
|> Enum.sum()
end
end
p1data.()
|> Day12.solve()
|> IO.inspect(label: "\n*** Part 1 solution (example: 21)")
# 7633
p1data.()
|> Day12.solve2()
|> IO.inspect(label: "\n*** Part 2 solution (example: 525152)")
#