Coding intervals
Merge Intervals
LC 56. Sort by start. Speak the overlap test in one line, then code.
LC 56. Sort by start. Speak the overlap test in one line, then code.
LC 57. Three passes: before, merge-overlap, after. No extra sort.
LC 253. Min-heap of end times. Sweep-line alternative in 30 seconds.
Writes, reads, and notification fan-out for 10k concurrent meetings.