public interface TwoSum {
/**
* Stores @param input in an internal data structure.
*/
public void store(int input);
/**
* Returns true if there is any pair of numbers in the internal data structure which
* have sum @param test, and false otherwise.
* For example, if the numbers 1, -2, 3, and 6 had been stored,
* the method should return true for 4, -1, and 9, but false for 10, 5, and 0
*/
public boolean test(int test);
}