64 lines
1.5 KiB
Markdown
64 lines
1.5 KiB
Markdown
# AOC 2024 Day 13
|
|
|
|
```elixir
|
|
Mix.install([
|
|
{:nx, "0.9.2"}
|
|
])
|
|
```
|
|
|
|
## Section
|
|
|
|
```elixir
|
|
input = """
|
|
"""
|
|
```
|
|
|
|
```elixir
|
|
defmodule ClawContraption do
|
|
def part1(input), do: parse(input, 0) |> solve()
|
|
def part2(input), do: parse(input, 10000000000000) |> solve()
|
|
|
|
def parse(input, n) do
|
|
(for line <- (input |> String.trim() |> String.split("\n")), reduce: {[], []} do
|
|
{vecs, matrices} = acc ->
|
|
case line do
|
|
"Button " <> rest ->
|
|
[[_, a, b]] = Regex.scan(~r/[AB]: X\+(\d+), Y\+(\d+)/, rest)
|
|
v = [a, b] |> Enum.map(&String.to_integer(&1))
|
|
{[v | vecs], matrices}
|
|
"Prize: " <> rest ->
|
|
[[_, a, b]] = Regex.scan(~r/X=(\d+), Y=(\d+)/, rest)
|
|
v = [a, b] |> Enum.map(&String.to_integer(&1))
|
|
a = Nx.tensor(vecs, type: :f64) |> Nx.transpose()
|
|
b = Nx.tensor(v |> Enum.map(&(&1+n)), type: :f64)
|
|
{[], [{a, b} | matrices]}
|
|
_ -> acc
|
|
end
|
|
end |> elem(1))
|
|
end
|
|
|
|
def solve(systems) do
|
|
for {a, b} <- systems,
|
|
c = Nx.LinAlg.invert(a) |> Nx.dot(b) |> Nx.round(),
|
|
b_prime = Nx.dot(
|
|
a, c
|
|
) |> Nx.round() |> Nx.as_type(:f64),
|
|
c = Nx.as_type(c, :s64),
|
|
b == b_prime,
|
|
reduce: Nx.tensor(0, type: :s64)
|
|
do
|
|
acc2 ->
|
|
c |> Nx.dot(Nx.tensor([1, 3], type: :s64)) |> Nx.add(acc2)
|
|
end
|
|
end
|
|
end
|
|
|
|
```
|
|
|
|
```elixir
|
|
ClawContraption.part1(input)
|
|
```
|
|
|
|
```elixir
|
|
ClawContraption.part2(input)
|
|
```
|