N meetings in one room

Problem Statement

Pattern: Related: 919 · Meeting Rooms II

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Solution

static class Interval{  
   public int start;  
   public int end;  
   Interval(int s, int e) {  
      this.start = s;  
      this.end = e;  
   }  
}
 
public int maxMeetings(int[] start, int[] end, int n) {
	ArrayList<Interval> intervals = new ArrayList<>();
	int count = 1;
	
	for (int i = 0; i < n; i++)
		intervals.add(new Interval(start[i], end[i]));
	intervals.sort((Comparator.comparingInt(o -> o.end)));
	
	Interval prev = intervals.get(0);
	for(Interval curr : intervals)
		if(curr.start > prev.end) {
			count++;
			prev = curr;
		}
	
	return count;
}

Notes

• Sort intervals by their end.
• increase count, everytime you come across a valid interval i.e. `curr.start > prev.end
• if(curr.start > prev.end) will be false for the first element, so count is initialised to count = 1