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MOON - Moon Safari (easy) |
Air is a music duo from France. You will be told the secret of the critically acclaimed album Moon Safari: mathematics. The goal of your new task is to compute an ethereal sum.
Three trips on the moon are provided, Moon (easy), Moon1 (medium), Moon2 (hard) with different constraints.
Input
The first line contains an integer T, the number of test cases. On the next T lines, you will be given three integers N, a and r.
Output
Output T lines, one for each test case, with SN,a,r = sum( a^i i^r, for i in [1..N] ). Since the answer can get very big, output it modulo 109+7.
Example
Input: 2 3 4 5 6 7 8 Output: 16068 329990641
Explanation
The first case is, with N=3, a=4, r=5, about the sum : 4^1 × 1^5 + 4^2 × 2^5 + 4^3 × 3^5 = 4 + 512 + 15552 = 16068. The second case is, with N=6, a=7, r=8, about the sum : 7^1 × 1^8 + 7^2 × 2^8 + 7^3 × 3^8 + 7^4 × 4^8 + 7^5 × 5^8 + 7^6 × 6^8 + 7^7 × 7^8 = 204329992069 ≡ 329990641 (mod 10^9+7).
Constraints
1 < T×N < 10^6 1 < a < 10^9 1 < r < 10^9
Information
This trip can be obviously done with a O(T×N×log(r)) method and some interpreted languages. Good luck and have fun ;-)
Added by: | Francky |
Date: | 2014-06-07 |
Time limit: | 10s-20s |
Source limit: | 50000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: ASM64 |
Resource: | Own problem |