Maximum Number of Events That Can Be Attended
Recognize the pattern
Brute force idea
A straightforward first read of Maximum Number of Events That Can Be Attended is this: Try all assignments of events to days — exponential. Each event-day pair is a choice. That instinct is useful because it follows the prompt literally, but it usually keeps revisiting work the problem is begging you to organize.
Better approach
A calmer way to see Maximum Number of Events That Can Be Attended is this: Sort events by start day. For each day, add all events starting on that day to a min-heap (by end day). Attend the event ending soonest (pop heap). Skip expired events. The goal is not to be clever for its own sake, but to remember the one relationship that keeps the solution grounded as you move forward.
Key invariant
The truth you want to protect throughout Maximum Number of Events That Can Be Attended is this: On each day, attending the event with the earliest deadline maximizes future flexibility — it's the event you're most at risk of losing. Events with later deadlines can still be attended tomorrow. If that remains true after every update, the rest of the reasoning has a stable place to stand.
Watch out for
A common way to get lost in Maximum Number of Events That Can Be Attended is this: Attending events in order of start day instead of deadline — an event starting early but ending late should be deferred if another event is about to expire. Most mistakes here are not about syntax; they come from losing track of what your state, pointer, or structure is supposed to mean.