//Verify the Height Property of each node AVLTree contains correct value.
private static int TreeHeightVerification(AvlNode <int> node)
{
int h;
if (node.IsLeafNode())
{
Assert.AreEqual(node.Height, 1);
return(1);
}
if (node.HasOneChild())
{
if (node.Left != null)
{
h = TreeHeightVerification(node.Left) + 1;
}
else
{
h = TreeHeightVerification(node.Right) + 1;
}
Assert.AreEqual(node.Height, h);
return(h);
}
h = Math.Max(TreeHeightVerification(node.Left), TreeHeightVerification(node.Right)) + 1;
Assert.AreEqual(node.Height, h);
return(h);
}
//Verify that every subtree at given node has balancing factor with range of -2(exclusive) to 2(exclusive)
//This test relies on the Height property of AVL Tree, so it shall only be performed after the Height property
//has been verified by TreeHeightVerification method to ensure the correctness of this test.
private static void BalancingFactorVerification(AvlNode <int> node)
{
int bf;
bool res;
if (node == null)
{
return;
}
if (node.IsLeafNode())
{
return;
}
if (node.HasOneChild())
{
if (node.Left != null)
{
bf = node.Left.Height - 0;
res = bf > -2 && bf < 2;
Assert.IsTrue(res);
BalancingFactorVerification(node.Left);
return;
}
bf = 0 - node.Right.Height;
res = bf > -2 && bf < 2;
Assert.IsTrue(res);
BalancingFactorVerification(node.Right);
return;
}
bf = node.Left.Height - node.Right.Height;
res = bf > -2 && bf < 2;
Assert.IsTrue(res);
BalancingFactorVerification(node.Left);
BalancingFactorVerification(node.Right);
}