public void ConvertTree_ValidTree_ConvertsToCircularLinkedList()
{
// arrange
BinaryTreeNode root = new BinaryTreeNode("0-root");
root.Left = new BinaryTreeNode("1-left");
root.Right = new BinaryTreeNode("1-right");
root.Left.Left = new BinaryTreeNode("2-left-left");
root.Left.Right = new BinaryTreeNode("2-left-right");
root.Right.Left = new BinaryTreeNode("2-right-left");
root.Right.Right = new BinaryTreeNode("2-right-right");
root.Right.Right.Left = new BinaryTreeNode("3-right-right-left");
root.Right.Right.Left.Right = new BinaryTreeNode("4-right-right-left-right");
ListOperations ops = new ListOperations();
// act
ListOperations.LinkedListNode actual = ops.ConvertTree(root);
// assert
Assert.AreEqual(root.Value, actual.Value);
Assert.AreEqual(root.Left.Value, actual.Next.Value);
Assert.AreEqual(root.Right.Value, actual.Next.Next.Value);
Assert.AreEqual(root.Left.Left.Value, actual.Next.Next.Next.Value);
Assert.AreEqual(root.Left.Right.Value, actual.Next.Next.Next.Next.Value);
Assert.AreEqual(root.Right.Left.Value, actual.Next.Next.Next.Next.Next.Value);
Assert.AreEqual(root.Right.Right.Value, actual.Next.Next.Next.Next.Next.Next.Value);
Assert.AreEqual(root.Right.Right.Left.Value, actual.Next.Next.Next.Next.Next.Next.Next.Value);
Assert.AreEqual(root.Right.Right.Left.Right.Value, actual.Next.Next.Next.Next.Next.Next.Next.Next.Value);
Assert.AreEqual(actual, actual.Next.Next.Next.Next.Next.Next.Next.Next.Next);
}
public void InOrderTraversal_ValidTree_CorrectSequence()
{
// arrange
BinaryTreeNode root = new BinaryTreeNode("0-root");
root.Left = new BinaryTreeNode("1-left");
root.Right = new BinaryTreeNode("1-right");
root.Left.Left = new BinaryTreeNode("2-left-left");
root.Left.Right = new BinaryTreeNode("2-left-right");
root.Right.Left = new BinaryTreeNode("2-right-left");
root.Right.Right = new BinaryTreeNode("2-right-right");
root.Right.Right.Left = new BinaryTreeNode("3-right-right-left");
root.Right.Right.Left.Right = new BinaryTreeNode("4-right-right-left-right");
TreeTraversal traversal = new TreeTraversal();
// act
BinaryTreeNode[] levelFirst = traversal.InOrder(root).ToArray();
// assert
Assert.AreEqual(levelFirst[0].Value, "2-left-left");
Assert.AreEqual(levelFirst[1].Value, "1-left");
Assert.AreEqual(levelFirst[2].Value, "2-left-right");
Assert.AreEqual(levelFirst[3].Value, "0-root");
Assert.AreEqual(levelFirst[4].Value, "2-right-left");
Assert.AreEqual(levelFirst[5].Value, "1-right");
Assert.AreEqual(levelFirst[6].Value, "3-right-right-left");
Assert.AreEqual(levelFirst[7].Value, "4-right-right-left-right");
Assert.AreEqual(levelFirst[8].Value, "2-right-right");
}
public void Next_ValidValues_ReturnsCorrectSequence()
{
// arrange
BinaryTreeNode root = new BinaryTreeNode("0-root");
root.Left = new BinaryTreeNode("1-left");
root.Right = new BinaryTreeNode("1-right");
root.Left.Left = new BinaryTreeNode("2-left-left");
root.Left.Right = new BinaryTreeNode("2-left-right");
root.Right.Left = new BinaryTreeNode("2-right-left");
root.Right.Right = new BinaryTreeNode("2-right-right");
root.Right.Right.Left = new BinaryTreeNode("3-right-right-left");
root.Right.Right.Left.Right = new BinaryTreeNode("4-right-right-left-right");
InOrderEnumerator enumerator = new InOrderEnumerator(root);
// act
// assert
Assert.AreEqual(enumerator.Next().Value, "2-left-left");
Assert.AreEqual(enumerator.Next().Value, "1-left");
Assert.AreEqual(enumerator.Next().Value, "2-left-right");
Assert.AreEqual(enumerator.Next().Value, "0-root");
Assert.AreEqual(enumerator.Next().Value, "2-right-left");
Assert.AreEqual(enumerator.Next().Value, "1-right");
Assert.AreEqual(enumerator.Next().Value, "3-right-right-left");
Assert.AreEqual(enumerator.Next().Value, "4-right-right-left-right");
Assert.AreEqual(enumerator.Next().Value, "2-right-right");
}
public IEnumerable<BinaryTreeNode> PostOrder(BinaryTreeNode node)
{
//if (node == null) { return Enumerable.Empty<BinaryTreeNode>(); }
//return PostOrder(node.Left).Union(PostOrder(node.Right)).Union(new[] { node });
// non-recursive
Stack<BinaryTreeNode> nodes = new Stack<BinaryTreeNode>();
Stack<BinaryTreeNode> reverse = new Stack<BinaryTreeNode>();
nodes.Push(node);
while (nodes.Count > 0)
{
BinaryTreeNode current = nodes.Pop();
if (current.Left != null)
{
nodes.Push(current.Left);
}
if (current.Right != null)
{
nodes.Push(current.Right);
}
reverse.Push(current);
}
return reverse;
}
public IEnumerable<BinaryTreeNode> InOrder(BinaryTreeNode node)
{
//if (node == null) { return Enumerable.Empty<BinaryTreeNode>(); }
//return InOrder(node.Left)
// .Union(new[] { node })
// .Union(InOrder(node.Right));
// non-recursive
Stack<BinaryTreeNode> nodes = new Stack<BinaryTreeNode>();
BinaryTreeNode current = node;
while (current != null || nodes.Count > 0)
{
while (current != null)
{
nodes.Push(current);
current = current.Left;
}
current = nodes.Pop();
yield return current;
current = current.Right;
}
}
public List<List<BinaryTreeNode>> AllRootToLeafPaths(BinaryTreeNode root)
{
List<BinaryTreeNode> list = new List<BinaryTreeNode>();
List<List<BinaryTreeNode>> results = new List<List<BinaryTreeNode>>();
AllRootToLeafPaths(root, list, results);
return results;
}
public BinaryTreeNode Next()
{
if (m_current == null && m_nodes.Count == 0)
throw new InvalidOperationException();
while (m_current != null)
{
m_nodes.Push(m_current);
m_current = m_current.Left;
}
BinaryTreeNode returnValue = m_nodes.Pop();
m_current = returnValue.Right;
return returnValue;
}
public IEnumerable<BinaryTreeNode> LevelOrder(BinaryTreeNode root)
{
Queue<BinaryTreeNode> nodes = new Queue<BinaryTreeNode>();
nodes.Enqueue(root);
while (nodes.Count > 0)
{
BinaryTreeNode node = nodes.Dequeue();
if (node.Left != null)
{
nodes.Enqueue(node.Left);
}
if (node.Right != null)
{
nodes.Enqueue(node.Right);
}
yield return node;
}
}
public void AllRootToLeafPaths_ValidTree_CorrectSequence()
{
// arrange
BinaryTreeNode root = new BinaryTreeNode("0-root");
root.Left = new BinaryTreeNode("1-left");
root.Right = new BinaryTreeNode("1-right");
root.Left.Left = new BinaryTreeNode("2-left-left");
root.Left.Right = new BinaryTreeNode("2-left-right");
root.Right.Left = new BinaryTreeNode("2-right-left");
root.Right.Right = new BinaryTreeNode("2-right-right");
root.Right.Right.Left = new BinaryTreeNode("3-right-right-left");
root.Right.Right.Left.Right = new BinaryTreeNode("4-right-right-left-right");
TreeTraversal traversal = new TreeTraversal();
// act
List<List<BinaryTreeNode>> paths = traversal.AllRootToLeafPaths(root);
// assert
Assert.AreEqual(4, paths.Count);
Assert.AreEqual('0', paths[0][0].Value[0]);
Assert.AreEqual('1', paths[0][1].Value[0]);
Assert.AreEqual('2', paths[0][2].Value[0]);
Assert.AreEqual('0', paths[1][0].Value[0]);
Assert.AreEqual('1', paths[1][1].Value[0]);
Assert.AreEqual('2', paths[1][2].Value[0]);
Assert.AreEqual('0', paths[2][0].Value[0]);
Assert.AreEqual('1', paths[2][1].Value[0]);
Assert.AreEqual('2', paths[2][2].Value[0]);
Assert.AreEqual('0', paths[3][0].Value[0]);
Assert.AreEqual('1', paths[3][1].Value[0]);
Assert.AreEqual('2', paths[3][2].Value[0]);
Assert.AreEqual('3', paths[3][3].Value[0]);
Assert.AreEqual('4', paths[3][4].Value[0]);
}
public InOrderEnumerator(BinaryTreeNode root)
{
m_current = root;
m_nodes = new Stack<BinaryTreeNode>();
}
public void SameFringe_IdenticalTrees_ReturnsTrue()
{
// arrange
BinaryTreeNode a = new BinaryTreeNode("0-root");
a.Left = new BinaryTreeNode("1-left");
a.Right = new BinaryTreeNode("1-right");
BinaryTreeNode b = new BinaryTreeNode("0-root2");
b.Left = new BinaryTreeNode("1-left");
b.Right = new BinaryTreeNode("1-right");
TreeTraversal traversal = new TreeTraversal();
// act
// assert
Assert.IsTrue(traversal.SameFringe(a, b));
}
public void SameFringe_DifferentLeaves_ReturnsFalse()
{
// arrange
BinaryTreeNode a = new BinaryTreeNode("0-root");
a.Left = new BinaryTreeNode("1-left");
a.Right = new BinaryTreeNode("1-right");
BinaryTreeNode b = new BinaryTreeNode("0-root2");
b.Left = new BinaryTreeNode("1-leftdd");
b.Right = new BinaryTreeNode("1-right");
TreeTraversal traversal = new TreeTraversal();
// act
// assert
Assert.IsFalse(traversal.SameFringe(a, b));
}
public IEnumerable<BinaryTreeNode> PreOrder(BinaryTreeNode node)
{
if (node == null) { return Enumerable.Empty<BinaryTreeNode>(); }
return new[] { node }
.Union(PreOrder(node.Left))
.Union(PreOrder(node.Right));
// non-recursive
//Stack<BinaryTreeNode> nodes = new Stack<BinaryTreeNode>();
//nodes.Push(node);
//while (nodes.Count > 0)
//{
// BinaryTreeNode current = nodes.Pop();
// yield return current;
// if (current.Right != null)
// {
// nodes.Push(current.Right);
// }
// if (current.Left != null)
// {
// nodes.Push(current.Left);
// }
//}
}
private IEnumerable<string> Fringe(BinaryTreeNode n)
{
if (n.Left == null && n.Right == null)
{
return new[] { n.Value };
}
else
{
IEnumerable<string> result = Enumerable.Empty<string>();
if (n.Left != null)
{
result = result.Union(Fringe(n.Left));
}
if (n.Right != null)
{
result = result.Union(Fringe(n.Right));
}
return result;
}
}
private void AllRootToLeafPaths(BinaryTreeNode node, List<BinaryTreeNode> current, List<List<BinaryTreeNode>> paths)
{
// add node
current.Add(node);
// leaf
if (node.Left == null && node.Right == null)
{
paths.Add(current.ToList());
}
// recurse left
if (node.Left != null)
{
AllRootToLeafPaths(node.Left, current, paths);
}
// recurse right
if (node.Right != null)
{
AllRootToLeafPaths(node.Right, current, paths);
}
// remove node
current.Remove(node);
}
public bool SameFringe(BinaryTreeNode a, BinaryTreeNode b)
{
return Fringe(a).SequenceEqual(Fringe(b));
}