Easy 252题 Meeting Rooms

Question:

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.

Solution:

/**
 * 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; }
 * }
 */
public class Solution {
    public boolean canAttendMeetings(Interval[] intervals) {
        //sort
        /*
        for(int i=0;i<=intervals.length-2;i++)
        {
            for(int j=i+1;j<=intervals.length-1;j++)
            {
                if(intervals[i].start==intervals[j].start)
                    return false;
                if(intervals[i].start>intervals[j].start)