[Solution] Jogging CodeChef Solution

[Solution] Jogging CodeChef Solution

Alice jogs everyday to keep herself fit and active. She noticed that she burns X$X$ calories when jogging the first kilometer, and for K>1$K>1$, jogging the Kth$K^{th}$ kilometer burns calories equivalent to the total number of calories burned while jogging the first K−1$K-1$ kilometers.

What is the total number of calories that Alice burns after jogging for N$N$ kilometers? The answer can be very large, so report it modulo 109+7${10}^9+7$ (1000000007$1000000007$).

Input Format

• The first line of input will contain an integer T$T$ — the number of test cases. The description of T$T$ test cases follows.
• The first and only line of each test case contains two space-separated integers N$N$ and X$X$, as described in the problem statement.

Output Format

For each test case, output on a new line the total number of calories that Alice burns after jogging for N$N$ kilometers, modulo 109+7${10}^9+7$.