Meeting Rooms - Implementation

Here is the solution:

function canAttendMeetings(intervals)
 if length of intervals <= 1 then
 return true
 sort intervals by start time
 for i from 1 to length - 1
 if intervals[i].start < intervals[i-1].end then
 return false
 return true

Time: $O(n \log n)$ for sorting. Space: $O(1)$ extra.

Once sorted, any overlap must occur between adjacent meetings. If meeting $i$ starts before meeting $i-1$ ends, they conflict.