Count Days Spent Together

export function countDaysTogether(
  arriveAlice: string,
  leaveAlice: string,
  arriveBob: string,
  leaveBob: string,
): number {
  const numberOfDays = [0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
  function getDays(date: string) {
    let totalDays = 0;
    const [month, day] = date.split('-').map((v) => parseInt(v));
    for (let m = 1; m < month; m++) {
      totalDays += numberOfDays[m];
    }
    return totalDays + day;
  }
  const startDays = Math.max(getDays(arriveAlice), getDays(arriveBob));
  const endDays = Math.min(getDays(leaveAlice), getDays(leaveBob));
  return Math.max(endDays - startDays + 1, 0);
}