private void Delete(Node node, Int32 value)
{
var nodeToDelete = Find(node, value);
var leftMostChild = GetLeftMostChild(nodeToDelete.Right);
nodeToDelete.Value = leftMostChild.Value;
leftMostChild = null;
}
public void Insert(Int32 value)
{
if (root == null)
root = new Node(value);
else
Insert(root, value);
}
private Boolean Exists(Node node, Int32 value)
{
if (node == null)
return false;
if (node.Value == value)
return true;
return Exists(node.Left, value) || Exists(node.Right, value);
}
static void Main()
{
Console.WriteLine("Please paste the input:");
var N = int.Parse(Console.ReadLine());
var nodes = new Node<int>[N];
for (int i = 0; i < N; i++)
{
nodes[i] = new Node<int>(i);
}
for (int i = 1; i <= N - 1; i++)
{
string line = Console.ReadLine();
var lineParts = line.Split(' ');
int parentValue = int.Parse(lineParts[0]);
int childValue = int.Parse(lineParts[1]);
nodes[parentValue].Children.Add(nodes[childValue]);
nodes[childValue].HasParent = true;
}
// Root
var root = FindRoot(nodes);
Console.WriteLine("The rootis: {0}", root.Value);
// Leafs
var leafs = GetLeafs(nodes);
Console.Write("Leafs: ");
foreach (var leaf in leafs)
{
Console.Write("{0}, ", leaf.Value);
}
Console.WriteLine();
// Middle nodes
var middleNodes = GetMiddleNodes(nodes);
Console.Write("Middle nodes: ");
foreach (var node in middleNodes)
{
Console.Write("{0}, ", node.Value);
}
Console.WriteLine();
// Longest path
var longestPath = GetLongestPath(FindRoot(nodes));
Console.WriteLine("Number of levels: {0}", longestPath + 1);
}
private static int GetLongestPath(Node<int> root)
{
if (root.Children.Count == 0)
{
return 0;
}
int maxPath = 0;
foreach (var node in root.Children)
{
maxPath = Math.Max(maxPath, GetLongestPath(node));
}
return maxPath + 1;
}
private Node Find(Node node, Int32 value)
{
var currentNode = node;
while (currentNode != null)
{
if (currentNode.Value == value)
return currentNode;
else if (currentNode.Value > value)
return Find(node.Left, value);
else
return Find(node.Right, value);
}
return null;
}
public void LevelOrder(Node start)
{
var queue = new Queue<Node>();
queue.Enqueue(start);
while (queue.Count > 0)
{
var node = queue.Dequeue();
Console.Write(node.value + ", ");
var child = node.firstChild;
while (child != null)
{
queue.Enqueue(child);
child = child.nextSibling;
}
}
}
public void InOrder(Node start)
{
var child = start.firstChild;
if (child != null)
{
while (child.nextSibling != null)
{
InOrder(child);
child = child.nextSibling;
}
}
Console.Write(start.value + ", ");
if (child != null)
{
InOrder(child);
}
}
public Node InsertChild(Node parent, string value)
{
var newNode = new Node { value = value, parent = parent };
if (parent.firstChild == null)
{
parent.firstChild = newNode;
}
else
{
var child = parent.firstChild;
while (child.nextSibling != null)
{
child = child.nextSibling;
}
child.nextSibling = newNode;
}
return newNode;
}
static Node<int> FindRoot(Node<int>[] nodes)
{
var hasParent = new bool[nodes.Length];
foreach (var node in nodes)
{
foreach (var child in node.Children)
{
hasParent[child.Value] = true;
}
}
for (int i = 0; i < hasParent.Length; i++)
{
if (!hasParent[i])
{
return nodes[i];
}
}
throw new ArgumentException("No root in the tree!");
}
public int MinNode(Node node)
{
while (node.left != null)
node = node.left;
return node.data;
}
public int MaxNode(Node node)
{
while (node.right != null)
node = node.right;
return node.data;
}
public void levelorder(Node node)
{
Node cur = node;
Queue<Node> queue = new Queue<Node>();
int nextLevel = 1;
int curLevel;
queue.Enqueue(cur);
while (queue.Count > 0)
{
curLevel = nextLevel;
nextLevel = 0;
for (int i = 0; i < curLevel; i++)
{
cur = queue.Dequeue();
Console.Write(" {0} ", cur.data);
if (cur.left != null)
{
queue.Enqueue(cur.left);
nextLevel++;
}
if (cur.right != null)
{
queue.Enqueue(cur.right);
nextLevel++;
}
}
Console.WriteLine();
}
}
public Node InPreToBinaryTree(int[] pre, int[] inorder, int instart, int inend, ref int preIndex)
{
if (instart > inend)
return null;
Node node = new Node(pre[preIndex++]);
if (instart == inend)
return node;
int inIndex;
for (inIndex = 0; inIndex < inorder.Length; inIndex++)
{
if (inorder[inIndex] == node.data)
break;
}
node.left = InPreToBinaryTree(pre, inorder, instart, inIndex - 1, ref preIndex);
node.right = InPreToBinaryTree(pre, inorder, inIndex + 1, inend, ref preIndex);
return node;
}
private void buildTree()
{
int[] vals = { 6, 2, 8, 1, 3, 7, 10, 5, 4, 9 };
foreach (int data in vals)
{
root = insert(root, data);
}
}
public int preorderSuccBST(Node node)
{
Node cur = root;
if (node.left != null)
return node.left.data;
if (node.right != null)
return node.right.data;
Node succ = null;
while (cur != null)
{
if (cur.data > node.data)
{
if (cur.right != null)
succ = cur.right;
cur = cur.left;
}
else if (cur.data < node.data)
cur = cur.right;
else
break;
}
return (succ == null) ? -1 : succ.data;
}
public int preorderPredBST(Node node)
{
Node cur = root;
while (cur != null && cur != node)
{
if (cur.right == node && cur.left != null)
return MaxNode(cur.left);
if (cur.left == node || cur.right == node)
return cur.data;
if (cur.data > node.data)
cur = cur.left;
if (cur.data < node.data)
cur = cur.right;
}
return -1;
}
public void preorderIter(Node node)
{
Node cur = node;
Stack<Node> stk = new Stack<Node>();
stk.Push(cur);
Console.WriteLine("\nPreorder traversal iterative (using stack): ");
while (stk.Count > 0)
{
cur = stk.Pop();
Console.Write(" {0} ", cur.data);
if (cur.right != null)
stk.Push(cur.right);
if (cur.left != null)
stk.Push(cur.left);
}
}
//using 2 stacks (this can be done using 1 stack also)
public void postorderIter(Node node)
{
Node cur = node;
Console.WriteLine("\n Postorder iterative using two stack: ");
Stack<Node> stk = new Stack<Node>();
Stack<Node> rem = new Stack<Node>();
stk.Push(cur);
while (stk.Count > 0)
{
cur = stk.Pop();
rem.Push(cur);
if (cur.left != null)
stk.Push(cur.left);
if (cur.right != null)
stk.Push(cur.right);
}
while (rem.Count > 0)
{
Console.Write(" {0} ", rem.Pop().data);
}
}
private static List<Node<int>> GetLeafs(Node<int>[] nodes)
{
List<Node<int>> leafs = new List<Node<int>>();
foreach (var node in nodes)
{
if (node.Children.Count == 0)
{
leafs.Add(node);
}
}
return leafs;
}
public void postorderIterOneStack(Node node)
{
Console.WriteLine("\nPostorder iterative using only one stack: ");
Node cur = node;
Stack<Node> stk = new Stack<Node>();
do
{
while (cur != null)
{
if (cur.right != null)
stk.Push(cur.right);
stk.Push(cur);
cur = cur.left;
}
cur = stk.Pop();
if (cur.right != null && stk.Count > 0 && cur.right == stk.Peek())
{
stk.Pop();
stk.Push(cur);
cur = cur.right;
}
else
{
Console.Write(" {0} ", cur.data);
cur = null;
}
} while (stk.Count > 0);
}
//using stack, time: O(n) and space: O(1) (no extra space)
public void inorderIter(Node node)
{
Stack<Node> stk = new Stack<Node>();
Node cur = node;
bool done = false;
Console.WriteLine("\nIn order traversal using stack (iterative): ");
while (!done)
{
if (cur != null)
{
stk.Push(cur);
cur = cur.left;
}
else
{
if (stk.Count > 0)
{
cur = stk.Pop();
Console.Write(" {0} ", cur.data);
cur = cur.right;
}
else
done = true;
}
}
}
public void preorderMorris(Node node)
{
Node cur = node;
Console.WriteLine("\nPreorder traversal using Morris traversal (threaded binary tree): ");
while (cur != null)
{
if (cur.left == null)
{
Console.Write(" {0} ", cur.data);
cur = cur.right;
}
else
{
Node succ = cur.left;
while (succ.right != null && succ.right != cur)
succ = succ.right;
if (succ.right == null)
{
succ.right = cur;
Console.Write(" {0} ", cur.data);
cur = cur.left;
}
else if (succ.right == cur)
{
succ.right = null;
cur = cur.right;
}
}
}
}
public void inorderMorris(Node node)
{
Node cur = node;
Console.WriteLine("\nIn order traversal using Morris traversal (threaded binary tree): ");
while (cur != null)
{
if (cur.left == null)
{
Console.Write(" {0} ", cur.data);
cur = cur.right;
}
else
{
Node succ = cur.left;
while (succ.right != null && succ.right != cur)
succ = succ.right;
if (succ.right == null)
{
succ.right = cur; //form a thread between leaf nodes right to its successor
cur = cur.left;
}
else if (succ.right == cur)
{
succ.right = null; //remove thread formed previously
Console.Write(" {0} ", cur.data);
cur = cur.right;
}
}
}
}
public void preorderRecur(Node node)
{
if (node == null)
return;
Console.Write(" {0} ", node.data);
preorderRecur(node.left);
preorderRecur(node.right);
}
public Node(int data, Node left, Node right)
{
this.data = data;
this.left = left;
this.right = right;
}
public Node SortedArrToBinaryTree(int[] arr, int start, int end)
{
if (start > end)
return null;
int mid = (start + end) / 2;
Node node = new Node(arr[mid]);
node.left = SortedArrToBinaryTree(arr, start, mid - 1);
node.right = SortedArrToBinaryTree(arr, mid + 1, end);
return node;
}
public int inorderPredBST(Node node)
{
Node cur = root;
if (node.left != null)
return MaxNode(node.left);
Node pred = null;
while (cur != null)
{
if (cur.data < node.data)
{
pred = cur;
cur = cur.right;
}
else if (cur.data > node.data)
cur = cur.left;
else
break;
}
return (pred == null) ? -1 : pred.data;
}
private Node insert(Node node, int data)
{
if (node == null)
return new Node(data);
else
{
if (node.data >= data)
node.left = insert(node.left, data);
else
node.right = insert(node.right, data);
return node;
}
}
public int inorderSuccBST(Node node)
{
Node cur = root;
if (node.right != null)
return MinNode(node.right);
Node succ = null;
while (cur != null)
{
if (cur.data > node.data)
{
succ = cur;
cur = cur.left;
}
else if (cur.data < node.data)
{
cur = cur.right;
}
else
break;
}
return (succ == null) ? -1 : succ.data;
}