A car park charges as follows. Write parking_fee(minutes):
- the first 15 minutes are free (a stay of 15 minutes or less costs 0),
- otherwise the first hour (or any part of it) costs 3,
- every further hour or part of an hour costs 2,
- the fee for a single day never exceeds 20.
Examples
Input: minutes = 10
Output: 0
Input: minutes = 60
Output: 3
Input: minutes = 61
Output: 5
Input: minutes = 600
Output: 20
Explanation: 10 hours would be 3 + 9 * 2 = 21, capped at 20.
Constraints
0 <= minutes <= 1440(integer)
Goals
- Combine a grace period, a per-hour rule and a daily cap
- Round minutes up to whole hours with integer arithmetic