Charged Up Array - HackerEarth Problem Solution

You are given with an array $A$ of size $N$.An element $A_i$ is said to be charged if its value($A_i$) is greater than or equal to $K_i$. $K_i$ is the total number of subsets of array $A$, that consist of element $A_i$.
Total charge value of the array is defined as summation of all charged elements present in the array mod ${10}^9+7$.
Your task is to output the total charge value of the given array $A$.

INPUT FORMAT:

The first line of input contains number of test cases $T$.
The first line of each test case consists of $N$, the size of the array.
Next line contains $N$ space-separated integers corresponding to each element $A_i$.

OUTPUT FORMAT:

For each test case, output a single number corresponding to total charge value of the given array.

Charged Up Array - HackerEarth Problem Solution