# Combination Sum

Medium

## Question

Given a list of unique positive integers and a target, find all **unique combinations** in the list where its sum is equal to the target.

Input: `nums = [2, 3, 5], target = 8`

Output: `[[2, 2, 2, 2], [2, 3, 3], [3, 5]]`

There are 3 unique combinations that sum up to 8.

- 2 + 2 + 2 + 2
- 2 + 3 + 3
- 3 + 5

Input: `nums = [2, 4, 6, 8], target = 8`

Output: `[[2, 2, 2, 2], [2, 2, 4], [2, 6], [4, 4], [8]]`

There are 5 unique combinations that sum up to 8.

- 2 + 2 + 2 + 2
- 2 + 2 + 4
- 2 + 6
- 4 + 4
- 8

Input: `nums = [2, 4, 6, 8], target = 9`

Output: `[]`

There are no combinations that sum up to 9.

## Clarify the problem

What are some questions you'd ask an interviewer?

## Understand the problem

How many unique combinations are there when nums = [2, 3, 7] and target = 7?

1

2

3

4

All test cases pass! ðŸŽ‰

Time limit exceeded

InputExpected OutputActual Output

Standard OutputScroll down...

Login or signup to save your code.

## Uh oh... looks like you don't yet have access.

Not sure what this unlocks? Check out a free pattern section.