public class TwoSum {    private HashMap
     
       elements = new HashMap
      
       ();     public void add(int number) {        if (elements.containsKey(number)) {            elements.put(number, elements.get(number) + 1);        } else {            elements.put(number, 1);        }    }     public boolean find(int value) {        for (Integer i : elements.keySet()) {            int target = value - i;            if (elements.containsKey(target)) {                if (i == target && elements.get(target) < 2) {                    continue;                }                return true;            }        }        return false;    }}