Difficulty spread a16g

A difficulty spread is a set of difficulties in a beatmap within some range of star rating values. 2d58l

Ranked beatmaps have several requirements regarding difficulty spreads as per the ranking criteria:

• All required difficulty levels within the spread's range must be present.
• Difficulties lower than the lowest difficulty level required, as determined by the spread rules, are optional.
• No two adjacent beatmap difficulties may have a significant gap in difficulty.