public bool BstCheck(TreeNode root,int min = int.MinValue , int max = int.MaxValue)
{
if (root == null) {
return true;
}
if (root.val > max || root.val < min) {
return false;
}
if (root.left != null) {
if (root.left.val > root.val)
{
return false;
}
}
if (root.right != null) {
if (root.right.val < root.val)
{
return false;
}
}
return BstCheck(root.left,min,root.val) && BstCheck (root.right,root.val ,max);
}
public static void Main(string[] args)
{
TreeNode n1 = new TreeNode (1);
TreeNode n2 = new TreeNode (2);
TreeNode n3 = new TreeNode (3);
TreeNode n4 = new TreeNode (4);
TreeNode n5 = new TreeNode (5);
TreeNode n6 = new TreeNode (6);
n1.left = n2;
n1.right = n5;
n2.left = n3;
n2.right = n4;
n5.right = n6;
TreeOp o = new TreeOp ();
// o.Flatten (n1);
o.Flatten3 (n1);
var tmp = n1;
while (tmp != null) {
Console.WriteLine (tmp.val);
tmp = tmp.right;
}
// Console.WriteLine ("");
// var e = o.LevelOrder (n1);
// Console.WriteLine ("");
// o.PrintBst (n1);
}
public void Flatten3(TreeNode root)
{
if (root == null) { return; }
var right = root.right;
if (lastVisitedNode != null) {
lastVisitedNode.left = null;
lastVisitedNode.right = root;
}
lastVisitedNode = root;
Flatten3 (root.left);
Flatten3 (right);
}
public bool BstCheck2(TreeNode root,int[] last)
{
if (root == null) {
return true;
}
var left = BstCheck2 (root.left,last);
if (last[0] > root.val) {
return false;
}
last[0] = root.val;
var right = BstCheck2 (root.right, last);
return left && right;
}
public bool IsBalanced(TreeNode root)
{
if (root == null) {
return true;
}
if (Math.Abs (MaxDepth (root.left) - MaxDepth (root.right)) > 1) {
return false;
}
return IsBalanced (root.left) && IsBalanced (root.right);
}
public TreeNode TrimBst(TreeNode root, int min, int max)
{
if (root == null) {
return null;
}
root.left = TrimBst(root.left, min,max);
root.right = TrimBst(root.right, min,max);
if (root.val <= max && root.val >= min ) {
return root;
}
if (root.val < min) {
return root.right;
}
if (root.val > max) {
return root.left;
}
return null;
}
public void TreeLevelOrderPrintBottomUp(TreeNode root)
{
Queue<TreeNode> q = new Queue<TreeNode>();
Stack<string> stack = new Stack<string> ();
string tmp = "";
int curCount = 1;
int nextCount = 0;
if (root == null) {
return;
}
q.Enqueue (root);
while (q.Count > 0) {
var cur = q.Dequeue ();
curCount -= 1;
tmp += cur.val + " ";
var left = cur.left;
var right = cur.right;
if (left != null) {
q.Enqueue (left);
nextCount += 1;
}
if (right != null) {
q.Enqueue (right);
nextCount += 1;
}
if (curCount == 0) {
stack.Push (tmp.TrimEnd(' '));
tmp = "";
curCount = nextCount;
nextCount = 0;
}
}
foreach (var item in stack.ToList()) {
Console.WriteLine (item);
}
}
public void TreeLevelOrderPrint(TreeNode root)
{
Queue<TreeNode> q = new Queue<TreeNode>();
int curCount = 1;
int nextCount = 0;
if (root == null) {
return;
}
q.Enqueue (root);
while (q.Count > 0) {
var cur = q.Dequeue ();
curCount -= 1;
Console.Write (cur.val + " ");
var left = cur.left;
var right = cur.right;
if (left != null) {
q.Enqueue (left);
nextCount += 1;
}
if (right != null) {
q.Enqueue (right);
nextCount += 1;
}
if (curCount == 0) {
Console.WriteLine ("");
curCount = nextCount;
nextCount = 0;
}
}
}
public void PrintBst(TreeNode root)
{
if (root == null) {
return;
}
Console.Write (root.val + " ");
PrintBst (root.left);
PrintBst (root.right);
}
public int MinDepth(TreeNode root)
{
if (root == null) {
return 0;
}
int left = MinDepth (root.left) + 1;
int right = MinDepth (root.right) + 1;
if (left == 1) {
return right;
}
if (right == 1) {
return left;
} else {
return Math.Min(left,right);
}
}
public int MaxDepth(TreeNode root)
{
if (root == null) {
return 0;
}
int leftDepth = MaxDepth (root.left) + 1;
int rightDepth = MaxDepth (root.right) + 1;
return (int)Math.Max (leftDepth,rightDepth);
}
// public void Flatten(TreeNode root)
// {
// if (root == null) {
// return;
// }
// List<TreeNode> arr = new List<TreeNode> ();
// Flatten(root,arr);
//
// for (int i = 0; i < arr.Count ; i++) {
// if (i + 1 < arr.Count) {
// arr [i].right = arr [i + 1];
// arr [i].left = null;
// }
// }
//
// }
//
// public void Flatten(TreeNode root, TreeNode prev)
// {
// if (root == null) {
// return;
// }
//
// Console.WriteLine (root.val);
//
// Flatten (root.left,root);
// Flatten (root.right,root);
//
// }
public IList<IList<int>> LevelOrder(TreeNode root)
{
if (root == null) {
return new List<IList<int>> ();
}
IList<IList<int>> list = new List<IList<int>> ();
Queue<TreeNode> q = new Queue<TreeNode> ();
q.Enqueue (root);
List<int> tmpList = new List<int> ();
int level = 1;
int counting = 0;
while (q.Count > 0) {
var tmp = q.Dequeue ();
tmpList.Add (tmp.val);
level -= 1;
Console.WriteLine (tmp.val + " ");
if (tmp.left != null) {
q.Enqueue (tmp.left);
counting += 1;
}
if (tmp.right != null) {
q.Enqueue (tmp.right);
counting += 1;
}
if (level == 0) {
list.Add (tmpList);
tmpList = new List<int> ();
Console.WriteLine ("");
level = counting;
counting = 0;
}
}
return list;
}
public bool IsSameTree(TreeNode p, TreeNode q)
{
if (p == null && q == null) {
return true;
}
if (p == null && q != null) {
return false;
}
if (p != null && q == null) {
return false;
}
if (p.val != q.val) {
return false;
}
return IsSameTree (p.left, q.left) && IsSameTree (p.right, q.right);
}