// Private method that converts each node to a node in a RBTree
private void Convert(Node node, RBTree <T> tree)
{
if (node == null)
{
return;
}
Node copy = CopyNonDeleted(node);
// Case 2-node: create a black node
// Case 3-node: create a black node (with larger value) as parent and red child
// Case 4-node: create a black node (with middle value) as parent and two red children
if (copy.NumItems == 1)
{
tree.Add(copy.Items[0], RBTree <T> .Color.BLACK);
}
else if (copy.NumItems == 2)
{
tree.Add(copy.Items[1], RBTree <T> .Color.BLACK);
tree.Add(copy.Items[0], RBTree <T> .Color.RED);
}
else if (copy.NumItems == 3)
{
tree.Add(copy.Items[1], RBTree <T> .Color.BLACK);
tree.Add(copy.Items[0], RBTree <T> .Color.RED);
tree.Add(copy.Items[2], RBTree <T> .Color.RED);
}
// Run Convert for all children of a node
// Note that piece of sh- code also works for the root, as it only has one child
for (int i = 0; i < node.NumItems + 1; i++)
{
Convert(node.Children[i], tree);
}
}
// Returns an instance of RBTree (red-black tree) that is an isometry of the current tree
public RBTree <T> Convert()
{
RBTree <T> tree = new RBTree <T>();
Convert(root, tree);
return(tree);
}
private static void RunTests(int numTests)
{
while (numTests > 0)
{
numTests--;
Tree <int> tree = new Tree <int>();
List <int> list = new List <int>();
// Test delete without any items
tree.Delete(rand.Next());
// Insert 20 values into the tree (note that duplicate values are not inserted)
for (int i = 0; i < 20; i++)
{
int item = -1;
while (item < 0 || list.Contains(item))
{
item = rand.Next(100) + 1;
}
tree.Insert(item);
list.Add(item);
}
for (int i = 0; i < list.Count; i++)
{
Console.Write("{0} ", list[i]);
}
Console.WriteLine();
// Test printing
tree.Print();
// Test converting to Red-Black tree
RBTree <int> rbtree = tree.Convert();
rbtree.Print();
// Randomize for delete testing
list = Randomize <int>(list);
// Check if all items are in
for (int i = 0; i < list.Count; i++)
{
if (!tree.Contains(list[i]))
{
Console.WriteLine("Something horrible happened here.");
}
}
// Test delete
for (int i = 0; i < list.Count; i++)
{
tree.Delete(list[i]);
}
// Output the number of items
Console.WriteLine("The item count is (should be 0): {0}", tree.Size());
// Test inserting them back
for (int i = 0; i < list.Count; i++)
{
tree.Insert(list[i]);
}
// Output the number of items
Console.WriteLine("The item count is (should be {0}): {1}", list.Count, tree.Size());
Console.WriteLine();
}
}
