2022.7.5-----leetcode.729

 List<int[]> booked;//已预定区间

    public MyCalendar() {
        booked = new ArrayList<int[]>();
    }

    public boolean book(int start, int end) {
        for (int[] arr : booked) {
            int l = arr[0], r = arr[1];
            //对于每个区间，判断是否会重叠
            if ( start < r&&end> l ) {
                return false;
            }
        }
        booked.add(new int[]{start, end});
        return true;
    }