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|
require Integer
program =
File.stream!("inputs/day23.txt")
|> Enum.map(&String.trim(&1))
programLength = length(program)
step = fn {programCounter, a, b} ->
instruction = Enum.at(program, programCounter)
case instruction do
"hlf a" ->
{programCounter + 1, div(a, 2), b}
"tpl a" ->
{programCounter + 1, a * 3, b}
"inc a" ->
{programCounter + 1, a + 1, b}
"inc b" ->
{programCounter + 1, a, b + 1}
<<"jmp " <> offset::binary>> ->
{offset, ""} = Integer.parse(offset)
{programCounter + offset, a, b}
<<"jie a, " <> offset::binary>> ->
if Integer.is_even(a) do
{offset, ""} = Integer.parse(offset)
{programCounter + offset, a, b}
else
{programCounter + 1, a, b}
end
<<"jio a, " <> offset::binary>> ->
if a == 1 do
{offset, ""} = Integer.parse(offset)
{programCounter + offset, a, b}
else
{programCounter + 1, a, b}
end
end
end
{_, _, terminalState1} =
Stream.iterate({0, 0, 0}, &step.(&1))
|> Enum.find(fn {programCounter, _, _} -> programCounter >= programLength end)
IO.puts("Part 1: #{terminalState1}")
{_, _, terminalState2} =
Stream.iterate({0, 1, 0}, &step.(&1))
|> Enum.find(fn {programCounter, _, _} -> programCounter >= programLength end)
IO.puts("Part 2: #{terminalState2}")
|
