Geometric Series Modulo
Compute A + Aq + Aq2 + … + AqN−1 modulo 109+7.
Input: one line with three integers A, q, N.
Output: the series sum mod 109+7.
Constraints:
- 1 ≤ A, q ≤ 109
- 1 ≤ N ≤ 1018
Sample Tests
Input 1
1 2 10
Output 1
1023
Input 2
5 1 3
Output 2
15
Discussion (opens after you solve — no spoilers before)
No comments yet.