252. Meeting Rooms

Given an array of meeting time intervals consisting of start and end times [[s1,e1],[s2,e2],...] (s_i < e_i), determine if a person could attend all meetings.

For example,
Given [[0, 30],[5, 10],[15, 20]],
return false.

public class Solution {
    public boolean canAttendMeetings(Interval[] intervals) {
        if(intervals == null || intervals.length == 0) return true;
        Arrays.sort(intervals, new Comparator(){
            public int compare(Interval i1, Interval i2){
                return i1.start - i2.start;
            }
        });
        int end = intervals[0].end;
        // 检查每一个Interval
        for(int i = 1; i < intervals.length; i++){
            // 如果Interval的开始时间小于之前最晚的结束时间，就返回假
            if(intervals[i].start < end) return false;
            end = Math.max(end, intervals[i].end);
        }
        return true;
    }
}