public class Solution {
    // DO NOT MODIFY THE LIST. IT IS READ ONLY
    public ArrayList<Integer> twoSum(final List<Integer> A, int B) {
        Map<Integer,Integer> map = new HashMap<>();
        ArrayList<Integer> list = new ArrayList<>();
        for(int i = 0;i< A.size();i++){
            if(!map.containsKey(B-A.get(i))){
                if(!map.containsKey(A.get(i))){
                map.put(A.get(i),i);

                }
            }else{
                list.add(map.get(B-A.get(i))+1);
                list.add(i+1);
                return list;
            }
        }
        return list;
    }
}