Leetcode 252: 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.

 

/**
 * Definition for an interval.
 * public class Interval {
 *     public int start;
 *     public int end;
 *     public Interval() { start = 0; end = 0; }
 *     public Interval(int s, int e) { start = s; end = e; }
 * }
 */
public class Solution {
    public bool CanAttendMeetings(Interval[] intervals) {
        if (intervals == null || intervals.Length < 2) return true;
        
        var starts = new int[intervals.Length];
        var ends = new int[intervals.Length];
        
        for (int i = 0; i < intervals.Length; i++)
        {
            starts[i] = intervals[i].start;
            ends[i] = intervals[i].end;
        }
        
        Array.Sort(starts);
        Array.Sort(ends);
        
        int rooms = 0, j = 0;
        
        for (int i = 0; i < intervals.Length; i++)
        {
            if (starts[i] < ends[j])
            {
                rooms++;
                
                if (rooms > 1) break;
            }
            else
            {
                j++;
            }
        }
        
        return rooms == 1;
    }
}