aocpp/day05.cpp

#include <iostream>
#include <utility>

#include <intcode.hpp>
using namespace intcode;

namespace {

auto Compute(Machine machine, ValueType d) -> ValueType {
  ValueType last_output = -1;
  while (std::visit(overloaded{
    [](Halt) { return false; },
    [d, &machine](Input arg) {
      arg.pos = d;
      return true;
    },
    [&last_output](Output arg) {
      last_output = arg.val;
      return true;
    }},
    machine.Step()));
  return last_output;
}

} // namespace

auto main() -> int {
  auto machine = Machine{ParseStream(std::cin)};
  std::cout << "Part 1: " << Compute(machine, 1) << std::endl;
  std::cout << "Part 2: " << Compute(std::move(machine), 5) << std::endl;
}