<!-- livebook:{"file_entries":[{"name":"day6_example.txt","type":"attachment"},{"name":"day6_input.txt","type":"attachment"},{"name":"day7-ex.txt","type":"attachment"},{"name":"day7-in.txt","type":"attachment"},{"name":"day8-ex.txt","type":"attachment"},{"name":"day8-in.txt","type":"attachment"}]} -->
# Day 9
```elixir
Mix.install([
{:kino, "~> 0.14.2"},
{:kino_aoc, "~> 0.1.7"}
])
```
## Part 1
```elixir
{:ok, input} =
KinoAOC.download_puzzle("2024", "9", System.fetch_env!("LB_AOC_SESSION"))
input = "2333133121414131402"
input = input |> String.graphemes() |> Enum.map(&String.to_integer/1)
```
```elixir
defmodule Part1 do
def decompress(dense_format, type, counter \\ 0, acc \\ [])
def decompress([], _, _, acc), do: Enum.reverse(acc)
def decompress([count | rest], :file, file_number, acc) do
decompress(rest, :free, file_number + 1, prepend(acc, file_number, count))
end
def decompress([count | rest], :free, file_number, acc) do
decompress(rest, :file, file_number, prepend(acc, ".", count))
end
def fill(left, right, acc \\ [])
def fill(left = ["." | _], ["." | r_rest], acc), do: fill(left, r_rest, acc)
def fill([match | l_rest], [match | r_rest], acc) when match != "." do
fill(l_rest, r_rest, [match | acc], :match)
end
def fill(["." | l_rest], [right | r_rest], acc) do
fill(l_rest, r_rest, [right | acc])
end
def fill(left, ["." | r_rest], acc) do
fill(left, r_rest, acc)
end
def fill([left | l_rest], r_rest, acc) when left != "." do
fill(l_rest, r_rest, [left | acc])
end
def fill([match | l_rest], [match | r_rest], acc, :match) when match != "." do
fill(l_rest, r_rest, [match | acc], :match)
end
def fill(_, _, acc, :match), do: acc
def prepend(list, value, until, count \\ 0)
def prepend(list, value, until, count) when count < until do
prepend([value | list], value, until, count + 1)
end
def prepend(list, _, _, _), do: list
end
decomp = Part1.decompress(input, :file)
fill = Part1.fill(decomp, Enum.reverse(decomp)) |> Enum.reverse()
sum = fill
|> Enum.with_index()
|> Enum.reduce(0, fn {x, y}, acc -> x * y + acc end)
```
## Part 2
```elixir
defmodule Part2 do
def decompress(dense_format, type, counter \\ 0, acc \\ [])
def decompress([], _, _, acc), do: Enum.reverse(acc)
def decompress([count | rest], :file, file_number, acc) do
decompress(rest, :free, file_number + 1, prepend(acc, file_number, count))
end
def decompress([count | rest], :free, file_number, acc) do
decompress(rest, :file, file_number, prepend(acc, ".", count))
end
def fill(left, right, acc \\ [])
def fill(left = ["." | _], ["." | r_rest], acc), do: fill(left, r_rest, acc)
def fill([match | l_rest], [match | r_rest], acc) when match != "." do
fill(l_rest, r_rest, [match | acc], :match)
end
def fill(lfull = ["." | l_rest], rfull = [right | r_rest], acc) do
if count(lfull) >= count(rfull) do
fill(l_rest, r_rest, [right | acc])
else
fill(lfull, r_rest, acc)
end
end
def fill(left, ["." | r_rest], acc) do
fill(left, r_rest, acc)
end
def fill([left | l_rest], r_rest, acc) when left != "." do
fill(l_rest, r_rest, [left | acc])
end
def fill([match | l_rest], [match | r_rest], acc, :match) when match != "." do
fill(l_rest, r_rest, [match | acc], :match)
end
def fill(_, _, acc, :match), do: acc
# Counts first value
def count([value | rest]), do: count(rest, value, 1)
def count([value | rest], value, count), do: count(rest, value, count + 1)
def count(_, value, count) do
IO.inspect({value, count})
count
end
def prepend(list, value, until, count \\ 0)
def prepend(list, value, until, count) when count < until do
prepend([value | list], value, until, count + 1)
end
def prepend(list, _, _, _), do: list
end
result = decomp
|> Part2.fill(Enum.reverse(decomp)) |> Enum.reverse()
```
<!-- livebook:{"offset":3935,"stamp":{"token":"XCP.PM645U43AA1PbBmmZyOhkUaqqST0pEAG650eJzIMqa3qps8oB2UQ5Yv-b79YkXjnMK3lHoZbYIlDeRd7VhrsuGbO4ficda8MDeTV4vwzypMOnC74o-I","version":2}} -->
