public void CountReversePairs()
{
Assert.AreEqual(0, PuzzleUtility.CountReversePairs(new int[] { 1, 2, 3, 4, 5 }));
Assert.AreEqual(10, PuzzleUtility.CountReversePairs(new int[] { 5, 4, 3, 2, 1 }));
Assert.AreEqual(13, PuzzleUtility.CountReversePairs(new int[] { 1, 9, 2, 6, 0, 8, 1, 7 }));
}
