n one-day long events are to take place over m days. Each event has a simple date range r1-r2, such that 0 < r1 and r2 <= m, in which it can be scheduled to take place.
Determine whether it's possible to schedule each event exclusively on its own day.
This is a cumulative constraint with $p_i=c_i=1$ for all $i$ and $C=1$.