aocpp/day05.cpp

#include <iostream>
#include <utility>

#include <intcode.hpp>
using namespace intcode;

namespace {

auto compute(Machine machine, value_type d) -> value_type {
  value_type 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{parse_stream(std::cin)};
  std::cout << "Part 1: " << compute(machine, 1) << std::endl;
  std::cout << "Part 2: " << compute(std::move(machine), 5) << std::endl;
}