The int[] bag describes a bag of nonnegative integers. A bag is the same thing as a set, only it may contain repeated elements.
The order of elements in a bag does not matter.
Given two bags A and B, we say that A is a subbag of B if A can be obtained by erasing zero or more elements from B.
The weight of a bag is the sum of its elements.
Examples:
The bags (1,2,1,3,1) and (3,1,1,1,2) are the same, but different from the bag (1,2,3,3).
Bags (1,2) and (3,1,1) are subbags of the bag (1,2,1,3,1), but bag (1,2,2) is not.
The weight of the bag (1,2,1,3,1) is 1+2+1+3+1=8.
Write a method that will compute how many subbags of bag have a prime weight.
