# Day 02

```elixir
Mix.install([:kino_aoc])
```

## Section

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```elixir
{:ok, puzzle_input} =
  KinoAOC.download_puzzle("2024", "2", System.fetch_env!("LB_ADVENT_OF_CODE_SESSION"))
```

```elixir
inputs =
  puzzle_input
  |> String.split("\n", trim: true)
  |> Enum.map(fn row ->
    row
    |> String.split(" ", trim: true)
    |> Enum.map(&String.to_integer/1)
  end)
```

```elixir
defmodule Day02 do
  def correct?([a, b | _] = input) do
    cmp = if a > b, do: &>/2, else: &</2
    valid? = fn [c, d] -> abs(c - d) in 1..3 and cmp.(c, d) end

    input
    |> Enum.chunk_every(2, 1, :discard)
    |> Enum.all?(valid?)
  end
end
```

## Part 1

```elixir
Enum.count(inputs, &Day02.correct?/1)
```

## Part 2

```elixir
Enum.count(inputs, fn row ->
  Enum.any?(0..length(row), fn idx ->
    row |> List.delete_at(idx) |> Day02.correct?()
  end)
end)
```

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