Distributing Identical Coins
Count the ways to hand out N identical coins to K distinct children (children may receive zero), modulo 109+7.
Input: one line with two integers N and K.
Output: C(N+K−1, K−1) mod 109+7.
Constraints:
- 0 ≤ N ≤ 105
- 1 ≤ K ≤ 105
Sample Tests
Input 1
3 2
Output 1
4
Input 2
0 5
Output 2
1
Discussion (opens after you solve — no spoilers before)
No comments yet.