Combination Sum

public class Solution {
    public ArrayList<ArrayList<Integer>> combinationSum(int[] candidates, int target) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        ArrayList<ArrayList<Integer>> result = new ArrayList<ArrayList<Integer>>();
        Arrays.sort(candidates);
        helpler(result, new ArrayList<Integer>(), candidates, 0, target);
        return result;
    }
    private void helpler(ArrayList<ArrayList<Integer>> result, ArrayList<Integer> path, int[] candidates, int start, int target){
        if(target<0 || start >= candidates.length)
            return;
        if(target == 0)  //only when all the integers add up to target, add the set
        {
            ArrayList<Integer> temp = new ArrayList<Integer>(path);  //avoid Output Limit Exceeded
            result.add(temp);
        }
        else{
            for(int i=start; i<candidates.length; i++)
            {
                if(candidates[i] > target)
                    break;
                path.add(candidates[i]);
                helpler(result, path, candidates, i, target-candidates[i]);
                path.remove(path.size()-1);  //empty the ArrayList for next use
            }
        }
    }
}