```
public class TwoSum {
Map<Integer, Integer> numToCountMap = new HashMap<>();
Set<Integer> sums = new HashSet<>();
public void add(int number) {
for (Integer ele : numToCountMap.keySet()){
sums.add(number + ele);
}
Integer counts = numToCountMap.get(number);
counts = (counts == null) ? 1 : counts+1;
numToCountMap.put(number, counts);
}
public boolean find(int value) {
return sums.contains(value);
}
}
```

but I do not understand why OJ gives me a "Time Limit Exceeded". Any help will be greatly appreciated.