private static void layerTraverse_useQueue(TN head)
{
if (head == null)
{
return;
}
Queue <TN> queue = new Queue <TN>();
queue.Enqueue(head);
while (queue.Count > 0)
{
int length = queue.Count;
for (int i = 0; i < length; i++)
{
TN temp = queue.Dequeue();
print(temp.value);
if (temp.leftNode != null)
{
queue.Enqueue(temp.leftNode);
}
if (temp.rightNode != null)
{
queue.Enqueue((temp.rightNode));
}
}
}
}
private static void LNR_I(TN head)
{
if (head == null)
{
return;
}
Stack <TN> stack = new Stack <TN>();
TN temp = head;
while (stack.Count > 0 || temp != null)
{
if (temp == null)
{
temp = stack.Pop();
print(temp.value);
temp = temp.rightNode;
}
else
{
stack.Push(temp);
temp = temp.leftNode;
}
}
}
private static void NLR_R(TN head)
{
if (head == null)
{
return;
}
print(head.value);
NLR_R(head.leftNode);
NLR_R(head.rightNode);
}
private static void LRN_R(TN head)
{
if (head == null)
{
return;
}
LRN_R(head.leftNode);
LRN_R(head.rightNode);
print(head.value);
}
private static void LRN_I(TN head)
{
if (head == null)
{
return;
}
Stack <TN> stack = new Stack <TN>();
TN visitedTN = null;
TN temp = head;
while (stack.Count > 0 || temp != null)
{
if (temp == null)
{
temp = stack.Peek();
if (temp.rightNode != null && temp.rightNode != visitedTN)
{
temp = temp.rightNode;
stack.Push(temp);
temp = temp.leftNode;
continue;
}
// Traverse node and pop stack
temp = stack.Pop();
visitedTN = temp;
print(temp.value);
temp = null;
}
else
{
stack.Push(temp);
temp = temp.leftNode;
}
}
}
public static void Main2(string[] args)
{
/* 1
* | |
* 2 3
* | | | |
* 4 5 6 7
*/
TN head = new TN(1);
TN leftTN = new TN(2);
head.leftNode = leftTN;
TN rightTN = new TN(3);
head.rightNode = rightTN;
leftTN.leftNode = new TN(4);
leftTN.rightNode = new TN(5);
rightTN.leftNode = new TN(6);
rightTN.rightNode = new TN(7);
// Recursive Traverse
// NLR_R(head);
// LNR_R(head);
// LRN_R(head);
// Iterator Traverse
// NLR_I(head);
// LNR_I(head);
// LRN_I(head);
// layerTraverse_useQueue(head);
// layerTraverse_useTwoList(head);
}
private static void layerTraverse_useTwoList(TN head)
{
if (head == null)
{
return;
}
List <TN> traverseList = new List <TN>();
traverseList.Add(head);
while (traverseList.Count >= 0)
{
int len = traverseList.Count;
List <TN> savePresentLayerElementsList = new List <TN>();
// The number of the next layer must less than or equals to len * 2
// List<TN> savePresentLayerElementsList = new List<TN>(len << 1);
for (int i = 0; i < len; i++)
{
TN temp = traverseList[i];
print(temp.value);
if (temp.leftNode != null)
{
savePresentLayerElementsList.Add(temp.leftNode);
}
if (temp.rightNode != null)
{
savePresentLayerElementsList.Add((temp.rightNode));
}
}
traverseList = savePresentLayerElementsList;
}
}