I solved problem 519E - A and B and Lecture Rooms using the solution suggested by the editorial and still it is slow when compared to others solutions. The strange thing is that there are some cases with maximum N and M that take ~0.1s to run, but there are others that are way slower, even though N and M are not maximum.
My solution took ~1.6s while there are some that took ~0.1s.
Why is my solution so slow?
Thanks for the help.