public void TestPermCheck()
{
int[] A = new int[] { 4, 1, 3, 2 };
int expected = 1;
int actual = Lessons.PermCheck(A);
Assert.AreEqual(expected, actual);
A = new int[] { 4, 1, 3 };
expected = 0;
actual = Lessons.PermCheck(A);
Assert.AreEqual(expected, actual);
A = new int[] { 4, 1, 3, 2, 2 };
expected = 0;
actual = Lessons.PermCheck(A);
Assert.AreEqual(expected, actual);
}