利用java自带库进行排序

Collections.sort(intervals, new Comparator<Interval>(){    @Override    public int compare(Interval obj0, Interval obj1) {        return obj0.start - obj1.start;    }});

public static class Interval {       int start;        int end;        Interval() { start = 0; end = 0; }       Interval(int s, int e) { start = s; end = e; }    }