Combination Sum

Statement

Given an array of distinct integers, nums, and an integer, target, return a list of all unique combinations of nums where the chosen numbers sum up to the target. The combinations may be returned in any order.

An integer from nums may be chosen an unlimited number of times. Two combinations are unique if the frequency of at least one of the chosen integers is different.

Constraints:

• $1 \leq$ nums.length $\leq 30$
• $2 \leq$ nums[i] $\leq 40$
• $1 \leq$ target $\leq 40$
• All integers of nums are unique.

Examples