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SomeAssemblyRequired
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| defmodule SomeAssemblyRequired do | |
| import Bitwise | |
| def run(lines) do | |
| lines | |
| |> String.split("\n") | |
| |> Enum.reject(&(&1 == "")) | |
| |> Enum.reduce([], fn line, binding -> | |
| [operation_or_value, var] = line |> String.split("->") |> Enum.map(&String.trim/1) | |
| val = eval(operation_or_value, binding) | |
| Keyword.put(binding, String.to_atom(var), val) | |
| end) | |
| end | |
| def eval(operation_or_value, binding \\ []) do | |
| case String.split(operation_or_value) do | |
| [l, "AND", r] -> | |
| [l, r] = get_value([l, r], binding) | |
| l &&& r | |
| [l, "OR", r] -> | |
| [l, r] = get_value([l, r], binding) | |
| l ||| r | |
| [l, "LSHIFT", r] -> | |
| [l, r] = get_value([l, r], binding) | |
| l <<< r | |
| [l, "RSHIFT", r] -> | |
| [l, r] = get_value([l, r], binding) | |
| l >>> r | |
| ["NOT", value] -> | |
| value = get_value(value, binding) | |
| ~~~value &&& 0xFFFF | |
| _ -> | |
| String.to_integer(operation_or_value) | |
| end | |
| end | |
| defp get_value(list, binding) when is_list(list) do | |
| Enum.map(list, &get_value(&1, binding)) | |
| end | |
| defp get_value(string, binding) do | |
| if Regex.match?(~r/^\d+$/, string), | |
| do: String.to_integer(string), | |
| else: Keyword.get(binding, String.to_atom(string)) | |
| end | |
| end | |
| ExUnit.start() | |
| defmodule SomeAssemblyRequiredTest do | |
| use ExUnit.Case | |
| test "eval works" do | |
| assert 72 = SomeAssemblyRequired.eval("123 AND 456") | |
| assert 72 = SomeAssemblyRequired.eval("x AND 456", x: 123) | |
| assert 507 = SomeAssemblyRequired.eval("123 OR 456") | |
| assert 4 = SomeAssemblyRequired.eval("1 LSHIFT 2") | |
| assert 0 = SomeAssemblyRequired.eval("1 RSHIFT 2") | |
| assert 65534 = SomeAssemblyRequired.eval("NOT 1") | |
| assert 1111 = SomeAssemblyRequired.eval("1111") | |
| end | |
| test "it works" do | |
| input = """ | |
| 123 -> x | |
| 456 -> y | |
| x AND y -> d | |
| x OR y -> e | |
| x LSHIFT 2 -> f | |
| y RSHIFT 2 -> g | |
| NOT x -> h | |
| NOT y -> i | |
| """ | |
| assert %{d: 72, e: 507, f: 492, g: 114, h: 65412, i: 65079, x: 123, y: 456} == | |
| SomeAssemblyRequired.run(input) |> Enum.into(%{}) | |
| end | |
| end |
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