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

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

tag: interval

/**
 * Definition for an interval.
 * public class Interval {
 *     int start;
 *     int end;
 *     Interval() { start = 0; end = 0; }
 *     Interval(int s, int e) { start = s; end = e; }
 * }
 */
class Solution {
    public boolean canAttendMeetings(Interval[] intervals) {
        if (intervals == null || intervals.length == 0) return true;
        if (intervals.length == 1) return true;

        Arrays.sort(intervals, (a, b) -> (a.start - b.start));

        int end = intervals[0].end;

        for (int i = 1; i < intervals.length; i++){
            if (intervals[i].start < end) return false;
            end = intervals[i].end;
        }

        return true;
    }
}