Count of Subset Sum

Statement

Given a set of positive numbers nums and a value targetSum, count the total number of subsets of the given set whose sum is equal to the targetSum.

Let’s say you are given a set = $\{$ $1, 2, 3, 4$ $\}$ and a target sum = $4$. The output will be 2 as the following subsets:

• $\{$ $1, 3$ $\}$
• $\{$ 4 $\}$

will add up to make the desired sum.

Constraints:

• $1\leq$ nums.length $\leq 1000$
• $0\leq$ targetSum $\leq 10^5$
• $0\leq$ nums[i] $\leq 10^4$

Examples