Question

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.

Example 1:

Input: [[0,30],[5,10],[15,20]]
Output: false
Example 2:

Input: [[7,10],[2,4]]
Output: true

NOTE: input types have been changed on April 15, 2019. Please reset to default code definition to get new method signature.

Thinking:

  • Method 1:
public class MeetingRooms {
	public static boolean canAttend(int[][] intervals){
		if(intervals == null || intervals.length == 0) return true;
		for(int i = 1; i < intervals.length; i++){
			if(intervals[i][0] < intervals[i - 1][1])
				return false;
		}
		return true;
	}	
}

Second Time

  • Method 1: Sort 
      class Solution {
      public boolean canAttendMeetings(int[][] intervals) {
          int len = intervals.length;
          int[] startTime = new int[len];
          int[] endTime = new int[len];
          int count = 0;
          for(int[] interval: intervals){
              startTime[count] = interval[0];
              endTime[count++] = interval[1];
          }
          Arrays.sort(startTime);
          Arrays.sort(endTime);
          for(int i = 1; i < len; i++){
              if(startTime[i] < endTime[i - 1]) return false;
          }
          return true;
      }
  }