Problem 43. Subset Sum
Given a vector v of integers and an integer n, return the the indices of v (as a row vector in ascending order) that sum to n. If there is no subset in v that sums to n, return an empty matrix []. You can assume that the answer will always be unique.
Example:
>> v = [2, 3, 5]; >> n = 8; >> subset_sum(v, n) ans = 2 3
Solution Stats
Problem Comments
-
4 Comments
Use nchoosek instead of combnts or combnk
At first I thought that it was quite difficult to look for the sets of elements of any size (sets of 1 element, 2 elements and so on), but then I realised that any selection of the vector elements correspond to a binary code ('1' for selecting that element and '0' for not selecting it). To select all possible elements combinations I only need to use the binary code from 1 to 2^(1+length(v))-1.
At first I thought that it was quite difficult to look for the sets of elements of any size (sets of 1 element, 2 elements and so on), but then I realised that any selection of the vector elements correspond to a binary code ('1' for selecting that element and '0' for not selecting it). To select all possible elements combinations I only need to use the binary code from 1 to 2^(1+length(v))-1.
Solution Comments
Show commentsProblem Recent Solvers1937
Suggested Problems
-
6875 Solvers
-
What is the next step in Conway's Life?
655 Solvers
-
3030 Solvers
-
1665 Solvers
-
Find my daddy long leg (No 's')
2477 Solvers
More from this Author96
Problem Tags
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!