a flashcard the user just saw
the difficulty of the user's answer to the flashcard
represents learning buckets before the flashcard was seen.
Maps each flashcard in the map to a nonnegative integer
bucket number in the range [0...retiredBucket] inclusive.
Mutated by this method to put card
in the appropriate bucket,
as determined by the Modified-Leitner algorithm.
number of retired bucket. Must be an integer >= 0.
Generated using TypeDoc
Update step for the Modified-Leitner algorithm.