제로 아트 갤러리

function solution(arrive, patience) {
  var answer = 0;
  var arrIdx = arrive.map((time, idx) => [time, patience[idx]]);
  arrIdx.sort((a, b) => a[0] - b[0] || a[1] - b[1]);

  var waiting = [];
  var pating = [];

  for (let i = 0; i < arrIdx.length; i++) {
    var [arrTime, patiTime] = arrIdx[i];
    waiting.push(arrTime);
    pating.push(arrTime + patiTime);

    while (pating.length && pating[0] < arrTime) {
      waiting.shift();
      pating.shift();
    }

    if (waiting.length === 2) {
      waiting = waiting.slice(2);
      pating = pating.slice(2);
      answer += 2;
    }
  }
  return answer;
}