public static IEnumerable <string> DFSBinarySearchTreePostOrderIterative(BinarySearchTreeKey.Node node)
{
var visitedNodes = new List <string>();
var toBeVisitedNodes = new Stack <BinarySearchTreeKey.Node>();
var currentNode = node;
BinarySearchTreeKey.Node prevNode = null;
while (currentNode != null || toBeVisitedNodes.Any())
{
if (currentNode != null)
{
toBeVisitedNodes.Push(currentNode);
currentNode = currentNode.Left;
}
else
{
var stackTopNode = toBeVisitedNodes.Pop();
if (stackTopNode.Right != null && stackTopNode.Right != prevNode)
{
currentNode = stackTopNode.Right;
toBeVisitedNodes.Push(stackTopNode);
}
else
{
currentNode = stackTopNode;
visitedNodes.Add(currentNode.Key);
prevNode = currentNode;
currentNode = null;
}
}
}
return(visitedNodes);
}
public static IEnumerable <IEnumerable <string> > TraverseBinarySearchTreeByLevelRecursive(
BinarySearchTreeKey.Node node)
{
var toBeTraversedNodes = new Queue <BinarySearchTreeKey.Node>();
toBeTraversedNodes.Enqueue(node);
return(TraverseBinarySearchTreeByLevelRecursive(toBeTraversedNodes));
}
public static IEnumerable <string> DFSBinarySearchTreePostOrderRecursive(BinarySearchTreeKey.Node node)
{
var returnValue = new List <string>();
if (node == null)
{
return(Enumerable.Empty <string>());
}
returnValue.AddRange(DFSBinarySearchTreePostOrderRecursive(node.Left));
returnValue.AddRange(DFSBinarySearchTreePostOrderRecursive(node.Right));
returnValue.Add(node.Key);
return(returnValue);
}
public static IEnumerable <string> TraverseBinarySearchTreeIterative(BinarySearchTreeKey.Node node)
{
var traversedNodes = new List <string>();
var toBeTraversedNodes = new Queue <BinarySearchTreeKey.Node>();
toBeTraversedNodes.Enqueue(node);
while (!toBeTraversedNodes.Empty())
{
var currentNode = toBeTraversedNodes.Dequeue();
if (currentNode == null)
{
continue;
}
traversedNodes.Add(currentNode.Key);
toBeTraversedNodes.Enqueue(currentNode.Left);
toBeTraversedNodes.Enqueue(currentNode.Right);
}
return(traversedNodes);
}
public static IEnumerable <string> DFSBinarySearchTreePreOrderIterative(BinarySearchTreeKey.Node node)
{
var visitedNodes = new List <string>();
var toBeVisitedNodes = new Stack <BinarySearchTreeKey.Node>();
var currentNode = node;
while (currentNode != null || toBeVisitedNodes.Any())
{
if (currentNode != null)
{
visitedNodes.Add(currentNode.Key);
toBeVisitedNodes.Push(currentNode);
currentNode = currentNode.Left;
}
else
{
currentNode = toBeVisitedNodes.Pop();
currentNode = currentNode.Right;
}
}
return(visitedNodes);
}
public static IEnumerable <IEnumerable <string> > TraverseBinarySearchTreeByLevelIterative(BinarySearchTreeKey.Node node)
{
var traversedNodesByLevel = new List <List <string> >();
var toBeTraversedNodes = new Queue <BinarySearchTreeKey.Node>();
toBeTraversedNodes.Enqueue(node);
var currentLevelNodes = new Queue <BinarySearchTreeKey.Node>();
while (!toBeTraversedNodes.Empty())
{
while (!toBeTraversedNodes.Empty())
{
currentLevelNodes.Enqueue(toBeTraversedNodes.Dequeue());
}
traversedNodesByLevel.Add(new List <string>());
while (!currentLevelNodes.Empty())
{
var currentNode = currentLevelNodes.Dequeue();
if (currentNode == null)
{
continue;
}
traversedNodesByLevel.Last().Add(currentNode.Key);
if (currentNode.Left != null)
{
toBeTraversedNodes.Enqueue(currentNode.Left);
}
if (currentNode.Right != null)
{
toBeTraversedNodes.Enqueue(currentNode.Right);
}
}
}
return(traversedNodesByLevel);
}
