추석 트래픽

function solution(lines) {
  var answer = 0;
  const linesArr = lines.map((line) => {
    const splitted = line.split(" ");
    const endTime = new Date(splitted[0] + " " + splitted[1]).getTime();
    const duration = parseFloat(splitted[2].slice(0, -1)) * 1000;
    const startTime = endTime - duration + 1;
    return [startTime, endTime];
  });

  // 현재 시간
  let dateIter = linesArr[0][0];
  // 가장 빨리 끝나는 작업의 끝나는 시간
  let firstEnd = undefined;
  let maxCount = 0;
  let currentCount = 0;
  let tempCount = 0;
  while (dateIter <= linesArr[linesArr.length - 1][1]) {
    // 현재시간 + 1초
    const maxIter = dateIter + 999;
    for (let i = 0; i < linesArr.length; i++) {
      const startTime = linesArr[i][0];
      const endTime = linesArr[i][1];
      if (!(endTime < dateIter) && !(maxIter < startTime)) {
        //카운트
        currentCount++;
        //끝나는시간 업데이트
        if (endTime == dateIter) {
          continue;
        }
        if (firstEnd == undefined) {
          firstEnd = endTime;
        } else {
          firstEnd = Math.min(firstEnd, endTime);
        }
      }
    }
    if (currentCount > maxCount) maxCount = currentCount;
    if (firstEnd == undefined) {
      dateIter += 1000;
    } else {
      dateIter = firstEnd;
    }
    firstEnd = undefined;
    currentCount = 0;
  }
  return maxCount;
}