Practice
Resources
Contests
Online IDE
New
Free Mock
Events New Scaler
Practice
Improve your coding skills with our resources
Contests
Compete in popular contests with top coders
Events
Attend free live masterclass hosted by top tech professionals
New
Scaler
Explore Offerings by SCALER

# Combination Sum

Problem Description

Given an array of candidate numbers A and a target number B, find all unique combinations in A where the candidate numbers sums to B.

The same repeated number may be chosen from A unlimited number of times.

Note:

1) All numbers (including target) will be positive integers.

2) Elements in a combination (a1, a2, … , ak) must be in non-descending order. (ie, a1 ≤ a2 ≤ … ≤ ak).

3) The combinations themselves must be sorted in ascending order.

4) CombinationA > CombinationB iff (a1 > b1) OR (a1 = b1 AND a2 > b2) OR ... (a1 = b1 AND a2 = b2 AND ... ai = bi AND ai+1 > bi+1)

5) The solution set must not contain duplicate combinations.

Problem Constraints

1 <= |A| <= 20

1 <= A[i] <= 50

1 <= B <= 500

Input Format

The first argument is an integer array A.

The second argument is integer B.

Output Format

Return a vector of all combinations that sum up to B.

Example Input

Input 1:

```A = [2, 3]
B = 2
```

Input 2:

```A = [2, 3, 6, 7]
B = 7
```

Example Output

Output 1:

```[ [2] ]
```

Output 2:

```[ [2, 2, 3] , [7] ]
```

Example Explanation

Explanation 1:

```All possible combinations are listed.
```

Explanation 2:

```All possible combinations are listed.
```

NOTE: You only need to implement the given function. Do not read input, instead use the arguments to the function. Do not print the output, instead return values as specified. Still have a question? Checkout Sample Codes for more details.
Hints
• Hint 1
• Solution Approach
• Complete Solution

## Discussion

Free Mock Assessment
Fill up the details for personalised experience.
Phone Number *
OTP will be sent to this number for verification
+1 *
+1
Change Number
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
*Enter the expected year of graduation if you're student
Current Employer
Company Name
College/University Name
Job Title
Job Title
Software Development Engineer (Backend)
Software Development Engineer (Frontend)
Software Development Engineer (Full Stack)
Data Scientist
Android Engineer
iOS Engineer
Devops Engineer
Support Engineer
Research Engineer
Engineering Intern
QA Engineer
Co-founder
SDET
Product Manager
Product Designer
Backend Architect
Program Manager
Release Engineer