Zoo feeding round

Plan a zoo's feeding round: decide which keepers handle each scheduled feeding, and which feedings have to be retried.

keepers[i] = [shiftStart, shiftEnd, species] is keeper i (numbered from 0): the minutes at which the shift starts and ends, and the list of species the keeper is certified to feed. feedings lists the scheduled feedings as [time, duration, species], in non-decreasing order of time. dangerous lists the species whose feedings need two keepers at once; every other feeding needs one.

A keeper can take a feeding that runs from t to t + duration only if all of these hold:

• shiftStart <= t and t + duration <= shiftEnd;
• the keeper is certified for the species;
• the keeper is free: their previous feeding ended at least turnaround minutes before t (a keeper with no previous feeding is free).

When a feeding is handled, collect every keeper who can take it and prefer those who have fed fewest animals so far (each feeding a keeper has taken counts as 1), breaking ties by the lower keeper number. Take as many as the feeding needs. If fewer keepers can take it than it needs, nobody is assigned and the feeding is missed. A missed feeding is retried exactly once, 15 minutes later with the same duration and species, under the same rules. If the retry is missed too it is dropped.

Feedings are handled in order of time. At the same minute, original feedings come first (in their listed order), then retries (in the order of the feedings they retry). A retry is handled at its own time and sees everything assigned before it.

Input: keepers, feedings, dangerous, turnaround.

Output: a list with one entry per feeding, in the listed order: [start, assigned], where start is the minute the feeding actually happened (its time, or its time plus 15 if it was a retry) and assigned is the list of keeper numbers in increasing order. A dropped feeding is [-1, []].