java遍历list问题

        for (int i = 0; i <= max+1; i++) {
            list.add(i,0);
        }

        int c=0;
        for (Interval l : airplanes) {

            int start = l.start;
            int end = l.end;

            c++;
            System.out.println("第"+c+"次遍历开始");

            System.out.println("init data in ("+start+" , "+end+")");

            for (int i = start; i < end; i++) {

                list.add(i, list.get(i)+1);
                System.out.println("end ("+i+" <=> "+list.get(i)+")");
            }
        }
        return Collections.max(list);