§ Cost of looping over all multiples of for in to
- Intuitively, when I think of "looping over and all its multiples", I seem to have a gut feeling that its cost is . Of course, it is not. It is .
- Thus, the correct total cost becomes (versus the false cost of .
- The correct total cost is a harmonic series .
- This is useful for number theory problems like 1627D