Java puzzler. From a Google Tech Talk.

ShortsPuzzle.java

import java.util.Set;
import java.util.HashSet;

public class ShortsPuzzle {
    public static void main(String[] args) {
        Set<Short> shortSet = new HashSet<Short>();
        for (short i = 0; i < 100; i++)
        {
            shortSet.add(i);
            shortSet.remove(i - 1);
        }

        System.out.println(shortSet.length());
    }
}

/*

What will this program output?
a) 0
b) 1
c) 100
d) None of the above

"None of the above" could mean that it outputs something not in the answer
choices, throws an exception, or varies from run to run.
It does not include the possibility of the program failing to compile.

*/