Combination Sum IV

Given an array of distinct integers nums and a target integer target, return the number of possible combinations that add up to target.

The test cases are generated so that the answer can fit in a 32-bit integer. Note that different sequences are counted as different combinations.

Examples
Input: [[1,2,3],4]
Output: 7
Hints

Combination Sum IV

Given an array of distinct integers `nums` and a target integer `target`, return the number of possible combinations that add up to `target`.