Ride queue board

Compute the wait times a theme park should post on its board right now, from the scans at the ride entrances and boarding gates.

Each scan is a string "<minute> <ride> <guest> <kind>", such as "615 comet-coaster g42 in". minute counts from park opening; kind is in (the guest scanned into the queue) or out (the guest scanned at the boarding gate). The scans were merged from several scanners, so they are not in time order. Only scans with minute <= now are known; ignore the rest. Process the known scans in increasing minute; scans with the same minute keep their order in scans.

A guest has at most one pending entry per ride:

• in when the guest is already pending on that ride is a duplicate scan and is ignored (the earlier time stands).
• in otherwise makes the guest pending, starting at that minute.
• out when the guest is pending finishes a wait of out minute - in minute minutes and ends the pending entry. An out with no pending entry is ignored.

Guests whose id starts with fp hold fast passes. Their waits are finished like any other, but they are never used for the board. For each ride, the usable waits are the non-fast-pass waits whose out minute is greater than now - 45. The ride's posted wait is the mean of its (up to) four usable waits with the latest out minutes (a later scan counts as later when minutes are equal), rounded to the nearest multiple of 5, with a mean exactly halfway between two multiples rounded up. A ride with no usable waits posts -1.

Input: scans, a list of strings, and now, an integer.

Output: a list [ride, posted] for every ride that has at least one known scan, ordered by posted ascending with rides that post -1 last; equal posted waits are ordered alphabetically by ride name. Return [] if there are no known scans.