Parcel Locker Bank

Run the log of a parcel locker bank: assign drop-offs to lockers, let uncollected parcels expire, and answer pickups.

The bank has numbered lockers (starting at 1) of sizes S, M and L; lockers[i] is the size of locker i + 1. A parcel fits any locker at least as large as itself (S < M < L). Each locker holds at most one parcel. hold and cleaning are numbers of minutes. Events arrive in non-decreasing time order; events with the same time are processed in the order given.

• A parcel dropped at minute t expires at minute t + hold if it has not been collected. Before processing any event at minute m, every parcel with expiry <= m has been removed from its locker and returned to the sender.
• After a locker is emptied, whether by a pickup at minute m or by an expiry at minute e, it needs cleaning: it cannot take a new parcel before minute m + cleaning (respectively e + cleaning). Note that e is the expiry minute, not the time of the next event.

Each event produces one output string:

• ["drop", t, size, id]: if a parcel with this id is currently in a locker, output DUPLICATE and do nothing. Otherwise look at the lockers that are empty, not being cleaned, and large enough; choose the smallest size, and among those the lowest number. Store the parcel there and output LOCKER <n>. If none is available, output FULL.
• ["pickup", t, id]: if the parcel is in a locker, empty it and output OPEN <n>. Otherwise, if the most recent parcel with that id was removed by expiry, output EXPIRED; in every other case (never seen, or already collected) output NONE. Dropping an id again starts a fresh record for it.

Input: lockers, a string of sizes; hold; cleaning; events, a list of events as above.

Output: a list of strings, one per event.