### Question:
SumSquareDifferenceAlgorithm extends AlgorithmLevelImpl { @Override public String get(int input) { long sum = 0; long sum2 = 0; for (int i = 1; i <= input; i++) { sum += i; sum2 += i * i; } return Long.toString(sum * sum - sum2); }  @Override String get(int input); @Override String description(); @Override int complexity(); @Override String author();  }### Answer:
@Test public void shouldWork() { int[] primes = new int[]{0, 0, 4, 22, 70, 170, 350, 644, 1092, 1740, 2640, 3850, 5434, 7462, 10010, 13160, 17000, 21624}; SumSquareDifferenceAlgorithm algorithm = new SumSquareDifferenceAlgorithm(); Assertions.assertAlgorithm(primes, algorithm); assertEquals("25164150", algorithm.get("100")); assertEquals("250166416500", algorithm.get("1000")); assertEquals("2500166641665000", algorithm.get("10000")); }