Find the Number of Possible Ways for an Event
hard · 34.9% accepted · 75 likes · top 13%
math · dynamic programming · combinatorics
Description
You are given three integers n, x, and y.
An event is being held for n performers. When a performer arrives, they are assigned to one of the x stages. All performers assigned to the same stage will perform together as a band, though some stages might remain empty.
After all performances are completed, the jury will award each band a score in the range [1, y].
Return the total number of possible ways the event can take place.
Since the answer may be very large, return it modulo 109 + 7.
Note that two events are considered to have been held differently if either of the following conditions is satisfied:
- Any performer is assigned a different stage.
- Any band is awarded a different score.
Solution