Advent of Code 2022 - Day 6

Day 6: Tuning Trouble

Description

Utils

defmodule Load do
  def file(path) do
    File.read!(__DIR__ <> path)
  end
end

Input

input = Load.file("/data/day06.txt")

Part 1

How many characters need to be processed before the first start-of-packet marker is detected? A start-of-packet marker is 4 unique character in a row.

index =
  input
  |> String.to_charlist()
  |> Enum.chunk_every(4, 1)
  |> Enum.find_index(fn code ->
    Enum.uniq(code) == code
  end)

index + 4

Result

1531

Part 2

How many characters need to be processed before the first start-of-message marker is detected? A start-of-message marker is 14 unique character in a row.

index =
  input
  |> String.to_charlist()
  |> Enum.chunk_every(14, 1)
  |> Enum.find_index(fn code ->
    Enum.uniq(code) == code
  end)

index + 14

Result

2518