Combination Sum IV

arraydynamic programming

Problem Statement

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.

Examples

Example 1

Input: nums = [1,2,3], target = 4
Output: 7
The possible combination ways are:
(1, 1, 1, 1)
(1, 1, 2)
(1, 2, 1)
(1, 3)
(2, 1, 1)
(2, 2)
(3, 1)
Note that different sequences are counted as different combinations.

Example 2

Input: nums = [9], target = 3
Output: 0

Constraints

1 <= nums.length <= 200

1 <= nums[i] <= 1000

All the elements of nums are unique .

1 <= target <= 1000

Follow up: What if negative numbers are allowed in the given array? How does it change the problem? What limitation we need to add to the question to allow negative numbers?

🤔

Medium

Difficulty

Topic Info

ModuleDSA

CategoryArray

Sub-topicDynamic Programming