public bool Insert(int iKey, Data data)
{
if (data == null)
{
return false;
}
Node n = new Node(iKey,data);
return Insert(n);
}
public void InOrderTraversal(Node n)
{
if (n == null)
{
return;
}
InOrderTraversal(n.left);
_visit.VisitNode(n,_que);
InOrderTraversal(n.right);
}
public void VisitNode(Node n, Queue<int> queue)
{
if ((n == null)||(queue == null))
{
throw new ArgumentNullException();
}
queue.Enqueue(n.iKey);
return;
}
public void VisitNode_Enqueues_Int()
{
// Arrange
Node node = new Node();
Queue<int> queue = new Queue<int>();
Visit v = new Visit(); // Class being tested...
// Act
Assert.IsTrue(queue.Count == 0);
v.VisitNode(node, queue);
//Assert
Assert.IsTrue(queue.Count == 1);
}
public void VisitNode_Throws_ArgumentNullException_On_Null_Queue()
{
// Arrange
Node n = new Node();
Visit v = new Visit(); // Class being tested...
// Act/Assert
try
{
v.VisitNode(n, null);
}
catch (Exception e)
{
Assert.IsTrue(e.GetType() == typeof(ArgumentNullException));
return;
}
Assert.Fail();
}
public bool Insert(Node n)
{
if (_tree == null)
{
_tree = n; // tree was empty (null), so n is first element.
return true;
}
Node current = _tree;
Node parent = null;
bool inserted = false;
while (true)
{
parent = current;
if (current.iKey == n.iKey)
{
return true; // Element (node) is already in tree.
}
if (current.iKey > n.iKey)
{
current = current.left;
if (current == null)
{
parent.left = n; // Less-than insert left.
inserted = true;
break;
}
}
else
{
current = current.right;
if (current == null)
{
parent.right = n;
inserted = true;
break;
}
}
}
return inserted;
}
public void InOrderTraversal(Node n)
{
Stack<Node> s = new Stack<Node>();
while ((s.Count > 0)||(n != null))
{
if (n != null)
{
s.Push(n);
n = n.left;
}
else // Get here if (n==null), so stack is not empty.
{
n = s.Pop();
_visit.VisitNode(n, _que);
n = n.right;
}
}
}
public void VisitNode_Enqueues_Ints_InOrder()
{
// Arrange
Node node1 = new Node();
Node node2 = new Node();
Queue<int> queue = new Queue<int>();
Visit v = new Visit(); // Class being tested...
node1.iKey = 1;
node2.iKey = 2;
// Act
v.VisitNode(node1, queue);
v.VisitNode(node2, queue);
//Assert
int i1 = queue.Dequeue();
int i2 = queue.Dequeue();
Assert.IsTrue(i1 == 1);
Assert.IsTrue(i2 == 2);
}
public bool FindNodeAndParent(Node tree, Node n, ref Node parent)
{
if (tree == null) // Check for empty tree.
{
parent = null;
return false;
}
if (tree == n)
{
return true;
}
parent = tree;
bool found;
if (tree.iKey > n.iKey)
{
if (tree.left != null)
{
found = FindNodeAndParent(tree.left, n, ref parent);
if (found == true)
{
return true;
}
}
}
if (tree.right != null)
{
found = FindNodeAndParent(tree.right, n, ref parent);
if (found == true)
{
return true;
}
}
return false;
}
// FindNodeyValue() is a pre-order recursive search. In a well balanced tree this is O(log number-of-nodes).
private Node FindNodeByValue(Node tree, int iKey)
{
if (tree == null)
{
return null;
}
if (iKey == tree.iKey) // Check for match.
{
return tree;
}
if (iKey < tree.iKey) // Check to see if we need to go look left.
{
return FindNodeByValue(tree.left, iKey);
}
// Only case left is to check the right branch of the tree.
return FindNodeByValue(tree.right, iKey);
}
public void Test_Remove_On_Node_With_Only_A_Right_Subtree()
{
// Arrange
BinaryTree bt = new BinaryTree();
Node n1 = new Node(17);
Node n2 = new Node(23); // This is the node we will delete.
Node n3 = new Node(29);
// This order of insertion should create a right-only subtree.
bt.Insert(n1);
bt.Insert(n2);
bt.Insert(n3);
// Act
bool removed = bt.Remove(23);
// Assert
Assert.IsTrue(removed);
Assert.IsTrue(bt.TreeDepth() == 2);
}
public void Test_Remove_On_Root_Node_With_Left_and_right_Subtrees()
{
// Arrange
BinaryTree bt = new BinaryTree();
// The test tree looks like:
// 11
// / \
// 5 17
// / \
// 2 7
// / \
// 1 4
// /
// 3
Node[] nArray = new Node[8];
nArray[0] = new Node(11); // This is the node we will delete below (root node).
nArray[1] = new Node(5);
nArray[2] = new Node(17);
nArray[3] = new Node(2);
nArray[4] = new Node(7);
nArray[5] = new Node(1);
nArray[6] = new Node(4);
nArray[7] = new Node(3);
// This order of insertion should create a our "complex" tree.
for (int i = 0; i < 8; i++)
{
bt.Insert(nArray[i]);
}
// Act
bool removed = bt.Remove(11);
// Assert
Assert.IsTrue(removed);
Queue<Node> queue = bt.TreeToQueue(); // Get the remaining elements to validate them...
Assert.IsTrue(queue.Count == 7);
Assert.IsTrue(1 == queue.Dequeue().iKey);
Assert.IsTrue(2 == queue.Dequeue().iKey);
Assert.IsTrue(3 == queue.Dequeue().iKey);
Assert.IsTrue(4 == queue.Dequeue().iKey);
Assert.IsTrue(5 == queue.Dequeue().iKey);
Assert.IsTrue(7 == queue.Dequeue().iKey);
Assert.IsTrue(17 == queue.Dequeue().iKey);
}
public void Test_TreeIsBalanced1_For_Single_Node_Tree()
{
// Arrange
BinaryTree b = new BinaryTree();
Node tree = new Node();
// Act
bool balanced = b.TreeIsBalanced1();
// Assert
Assert.IsTrue(balanced);
}
private bool TreeIsBalancedInternal2(Node t, ref int depth)
{
if (t == null)
{
depth = 0;
return true;
}
int depthL = 0;
int depthR = 0;
if (TreeIsBalancedInternal2(t.left,ref depthL)&&(TreeIsBalancedInternal2(t.right,ref depthR)))
{
int diff = Math.Abs(depthL - depthR);
if (diff <= 1)
{
depth = 1 + (Math.Max(depthL, depthR));
return true;
}
}
return false;
}
private int TreeDepthInternal(Node t)
{
if (t == null)
{
return 0;
}
int dLeft = TreeDepthInternal(t.left);
int dRight = TreeDepthInternal(t.right);
return Math.Max(dLeft, dRight) + 1; // Plus one for this node...
}
public void Test_Remove_On_Node_With_Only_A_Left_Subtree()
{
// Arrange
BinaryTree bt = new BinaryTree();
Node n1 = new Node(17);
Node n2 = new Node(14); // This is the one we will remove.
Node n3 = new Node(9);
// This order of insertion should create a left-only subtree.
bt.Insert(n1);
bt.Insert(n2);
bt.Insert(n3);
// Act
bool removed = bt.Remove(14);
// Assert
Assert.IsTrue(removed);
Assert.IsTrue(bt.TreeDepth() == 2);
Queue<Node> queue = bt.TreeToQueue();
Assert.IsTrue(queue.Dequeue() == n3);
Assert.IsTrue(queue.Dequeue() == n1);
}
public bool Remove(int iKey)
{
Node nRemove = FindNodeByValue(_tree, iKey); // XXX: Dorky code. Combine this and next method call.
Node parent = null;
bool found = FindNodeAndParent(_tree, nRemove, ref parent);
if (found == false)
{
// Either the tree is empty or the node doesn't exist in the tree.
return false;
}
// Ok, node was found.
if (parent == null)
{
// Tree is a single node tree.
_tree = null;
return true;
}
// Case #1: Node n is a leaf (no children)
if ( (nRemove.left == null) && (nRemove.right == null))
{
if (parent.left == nRemove)
parent.left = null;
else
parent.right = null;
return true;
}
// Case #2: Node n has either a left or right child but not both.
if((nRemove.left != null) && (nRemove.right == null))
{
if (parent.left == nRemove)
{
parent.left = nRemove.left;
}
else
{
parent.right = nRemove.left;
}
return true;
}
if ((nRemove.left == null) && (nRemove.right != null))
{
if (parent.left == nRemove)
{
parent.left = nRemove.right;
}
else
{
parent.right = nRemove.right;
}
return true;
}
// Case #3: The node has both left and right children.
// Find the largest value in the left subtree, copy its data into the node being "removed" then
// remove that largest node from the tree (note: it won't have a right subtree).
Node nLargest = nRemove.left;
Node nLargestParent = nRemove;
while (nLargest.right != null)
{
nLargestParent = nLargest;
nLargest = nLargest.right;
}
int tempValue = nLargest.iKey;
bool removed = Remove(nLargest.iKey);
nRemove.iKey = tempValue;
return true;
}
public bool TreeIsBalancedInternal1(Node t)
{
if (t == null)
{
return true;
}
int dLeft = TreeDepthInternal(t.left);
int dRight = TreeDepthInternal(t.right);
if (Math.Abs(dLeft - dRight) > 1)
{
return false;
}
else
{
return (TreeIsBalancedInternal1(t.left) && (TreeIsBalancedInternal1(t.right)));
}
}
private void InOrderTreeToQueue(Node t, Queue<Node> queue)
{
if (t != null)
{
InOrderTreeToQueue(t.left, queue);
queue.Enqueue(t);
InOrderTreeToQueue(t.right, queue);
}
}
public void Test_Remove_On_Node_With_Left_and_right_Leaves()
{
// Arrange
BinaryTree bt = new BinaryTree();
Node n1 = new Node(17);
Node n2 = new Node(23); // This is the node we will delete.
Node n3 = new Node(21);
Node n4 = new Node(29);
bt.Insert(n1);
bt.Insert(n2); // Node to delete.
bt.Insert(n3);
bt.Insert(n4);
// Act
bool removed = bt.Remove(23);
// Assert
Assert.IsTrue(removed);
Queue<Node> queue = bt.TreeToQueue(); // To validate the remaining tree nodes.
Assert.IsTrue(queue.Count == 3);
Assert.IsTrue(17 == queue.Dequeue().iKey);
Assert.IsTrue(21 == queue.Dequeue().iKey);
Assert.IsTrue(29 == queue.Dequeue().iKey);
}