Combination Sum in Java (Medium) Recursive Programming

Asked in:
Microsoft, Infosys, Amazon , Accolite ,  ABCQ

Question;

Given an array of integers A and a sum B, find all unique combinations in A where the sum is equal to B.

ach number in A may only be used once in the combination.

Note:
   All numbers will be positive integers.
   Elements in a combination (a1, a2, … , ak) must be in non-descending order. (ie, a1 ≤ a2 ≤ … ≤ ak).
   The combinations themselves must be sorted in ascending order.
   If there is no combination possible the print "Empty" (without qoutes).
Example,
Given A = 10,1,2,7,6,1,5 and B(sum) 8,

A solution set is:

[1, 7]
[1, 2, 5]
[2, 6]
[1, 1, 6]

Input:
First is T , no of test cases. 1<=T<=500
Every test case has three lines.
First line is N, size of array. 1<=N<=12
Second line contains N space seperated integers(x). 1<=x<=9.
Third line is the sum B. 1<=B<=30.
 
Output:
One line per test case, every subset enclosed in () and in every set intergers should be space seperated.(See example)

Example:
Input:
2
7
10 1 2 7 6 1 5
8
5
8 1 8 6 8
12

Output:
(1 1 6)(1 2 5)(1 7)(2 6)
Empty

Code:

import java.util.*;

import java.lang.*;

import java.io.*;

class GFG {

public static void main (String[] args) {

//code

Scanner sc  = new Scanner(System.in);

int  m  = sc.nextInt();

for (int i=0;i<m;i++){

   int n = sc.nextInt();//sze of array

   int [] ar= new int[n];

   for (int j=0;j<n;j++){

       ar[j] = sc.nextInt();

   }

   int tot = sc.nextInt();

  // Arrays.sort(ar);

   System.out.println(test(ar,tot));

}

}

public static void cs(List<List<Integer>> result, List<Integer> curr, int start, int target, int[] candidates){

    if(target==0){

        result.add(new ArrayList<Integer>(curr));

        return;

    }

    if(target<0){

        return;

    }

    int prev=-1;

    for(int i=start; i<candidates.length; i++){

        if(prev!=candidates[i]){ // each time start from different element

            curr.add(candidates[i]);

            cs(result, curr, i+1, target-candidates[i], candidates); // and use next element only

            curr.remove(curr.size()-1);

            prev=candidates[i];

        }

    }

}

public static List<List<Integer>> test (int [] arr , int tot){

   List<List<Integer>> res = new ArrayList<List<Integer>>();

   List<Integer> curr =  new ArrayList<Integer>();

   Arrays.sort(arr);

   cs(res,curr,0,tot,arr);//combibnation sum

   return res;

}

}