sourcema.md

leetcode 40

class Solution {
public List<List<Integer>> combinationSum2(int[] candidates, int target) {
     List<List<Integer>> res = new ArrayList<>();
    if (candidates == null || candidates.length == 0 || target <= 0) {
        return res;
    }
    Arrays.sort(candidates);//
    combination(res,candidates,new ArrayList<Integer>(),target,0);
    return res;
}
private static void combination(List<List<Integer>> res, int[] candidates, ArrayList<Integer> list,
                                int target, int index) {
    if (target == 0) {
        if (!res.contains(list))
        res.add(new ArrayList<Integer>(list));
        return;
    }
    if (index>=candidates.length||target < candidates[index]) {
        return;
    }
        list.add(candidates[index]);
        combination(res,candidates,list,target-candidates[index],index+1);
        list.remove(list.size() - 1);
        combination(res,candidates,list,target,index+1);
}

}