Leetcode: Meeting Rooms

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]],
return false.

Understand the problem:

The problem looks very similar to the merge interval and insert intervals. So the idea is still the same: first sort the intervals according to the start times, then check if there is any overlap. 

Code (Java):

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/**  * 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) {         if (intervals == null || intervals.length ==0) {             return true;         }                   // Sort according to the start time         Arrays.sort(intervals, new IntervalComparator());                   Interval prev = intervals[0];         for (int i = 1; i < intervals.length; i++) {             Interval curr = intervals[i];             if (isOverlapped(prev, curr)) {                 return false;             }             prev = curr;         }                   return true;     }           public class IntervalComparator implements Comparator<Interval> {         @Override         public int compare(Interval a, Interval b) {             return a.start - b.start;         }     }           private boolean isOverlapped(Interval a, Interval b) {         return a.end > b.start;     } }