function buffer2(xs) {
  
  const ys = xs.filter((_, i) => !(i % 2));
  const zs = xs.filter((_, i) => i % 2);
  let ws = [];

  for (let i = 0; i < ys.length; ++i) {
    ws.push([ys[i], zs[i]]);
  }
  return ws;
}

function parse(raw) {
  const [MAX_CAPACITY, rawRequests] = raw.split(/\r?\n/);
  const requests = buffer2(rawRequests.split(" ").map(v => parseInt(v))).map(
    ([id, size]) =>
      size
        ? { type: "allocate", payload: { id, size } }
        : { type: "free", payload: id }
  );
  return { MAX_CAPACITY, requests }
}

module.exports = parse;