# Advent of Code 2022 - Day 2
## Puzzle description
[Day 2: Rock Paper Scissors](https://adventofcode.com/2022/day/2).
## Input
```elixir
defmodule Input do
def load! do
"input/02.txt"
|> Path.expand(__DIR__)
|> File.stream!()
end
@doc """
Returns normalized output when generating streams from files or string input.
"""
def to_stream(input) when is_binary(input) do
input
|> String.trim("\n")
|> String.splitter("\n")
end
def to_stream(stream) do
stream
|> Stream.map(fn string -> String.trim_trailing(string, "\n") end)
end
def debug(stream) do
stream |> Enum.into([]) |> dbg()
stream
end
end
```
## Solution
```elixir
defmodule Part1 do
# preflight:
## split string into lines (without break characters)
def run(input) do
input
|> Stream.map(&check/1)
|> Enum.into([])
|> Enum.sum()
end
# Rocks: A X
# Papers: B Y
# Scissorses: C Z
# W: 6
# D: 3
# L: 0
# rock / rock, D
def check("A X"), do: 4
# rock / paper, W
def check("A Y"), do: 8
# rock / scissors, L
def check("A Z"), do: 3
# paper / rock, L
def check("B X"), do: 1
# paper / paper, D
def check("B Y"), do: 5
# paper / scissors, W
def check("B Z"), do: 9
# scissors / rock, W
def check("C X"), do: 7
# scissors / paper, L
def check("C Y"), do: 2
# scissors / scissors, D
def check("C Z"), do: 6
end
defmodule Part2 do
# preflight:
## split string into lines (without break characters)
def run(input) do
input
|> Stream.map(&check/1)
|> Enum.into([])
|> Enum.sum()
end
# rock / L, choose scissors
def check("A X"), do: 3
# rock / D, choose rock
def check("A Y"), do: 4
# rock / W, choose paper
def check("A Z"), do: 8
# paper / L, choose rock
def check("B X"), do: 1
# paper / D, choose paper
def check("B Y"), do: 5
# paper / W, choose: scissors
def check("B Z"), do: 9
# scissors / L, choose: paper
def check("C X"), do: 2
# scissors / D, choose: scissors
def check("C Y"), do: 6
# scissors / W, choose: rock
def check("C Z"), do: 7
end
ExUnit.start(autorun: false)
defmodule Test do
use ExUnit.Case, async: true
@example_input ~s(
A Y
B X
C Z
)
@input Input.load!()
test "part 1" do
assert @example_input |> Input.to_stream() |> Part1.run() === 15
@input |> Input.to_stream() |> Part1.run() |> dbg()
end
test "part 2" do
assert @example_input |> Input.to_stream() |> Part2.run() === 12
@input |> Input.to_stream() |> Part2.run() |> dbg()
end
end
ExUnit.configure(trace: true)
ExUnit.run()
```
