Balls | Boxes | Any way | At most one ball | At least one ball |
---|---|---|---|---|
Distinguishable | Distinguishable | 1 | 2 | 3 |
Indistinguishable | Distinguishable | 4 | 5 | 6 |
Distinguishable | Indistinguishable | 7 | 8 | 9 |
Indistinguishable | Indistinguishable | 10 | 11 | 12 |
You have $n$ balls and $k$ boxes. You want to put these balls into the boxes.
Find the number of ways to put the balls under the following conditions:
Note that you must print this count modulo $10^9+7$.
$n$ $k$
The first line will contain two integers $n$ and $k$.
Print the number of ways modulo $10^9+7$ in a line.
10 5
7
30 15
176
100 30
3910071