public TreeNodeWithNext(int data)
{
Data = data;
Left = null;
Right = null;
Next = null;
}
private void Connect(TreeNodeWithNext root)
{
if (root == null)
return;
Connect(root.Left, root);
Connect(root.Right, root);
Connect(root.Right);
Connect(root.Left);
}
private void Connect(TreeNodeWithNext current, TreeNodeWithNext parent)
{
if (current == null)
return;
if (current != parent.Right && parent.Right != null)
{
current.Next = parent.Right;
}
else
{
while (parent.Next != null)
{
parent = parent.Next;
if (parent.Left != null || parent.Right != null)
{
current.Next = parent.Left == null ? parent.Right : parent.Left;
break;
}
}
}
}
private TreeNodeWithNext ConnectRec(TreeNodeWithNext cur, TreeNodeWithNext parent)
{
if (parent != null && parent.Next != null)
{
while (parent.Next != null && parent.Next.Left == null && parent.Next.Right == null)
{
parent = parent.Next;
}
if (parent.Next != null)
{
if (parent.Next.Left != null)
{
cur.Next = parent.Next.Left;
}
else if (parent.Next.Right != null)
{
cur.Next = parent.Next.Right;
}
}
}
if (cur != null)
{
if (cur.Left != null && cur.Right != null)
{
cur.Left.Next = cur.Right;
ConnectRec(cur.Right, cur);
ConnectRec(cur.Left, null);
}
else if (cur.Left != null)
{
ConnectRec(cur.Left, cur);
}
else if (cur.Right != null)
{
ConnectRec(cur.Right, cur);
}
}
return cur;
}
private static void ConnectAtSameLevel(TreeNodeWithNext root)
{
if (root == null)
{
return;
}
Queue <TreeNodeWithNext> q = new Queue <TreeNodeWithNext>();
q.Enqueue(root);
q.Enqueue(null);
while (q.Count > 0)
{
TreeNodeWithNext current = q.Dequeue();
if (current != null)
{
current.Next = q.Peek();
if (current.Left != null)
{
q.Enqueue(current.Left);
}
if (current.Right != null)
{
q.Enqueue(current.Right);
}
}
else
{
if (q.Count > 0)
{
q.Enqueue(null);
}
}
}
}
static void Main(string[] args)
{
TreeNodeWithNext root = new TreeNodeWithNext(1);
var node2 = new TreeNodeWithNext(2);
var node3 = new TreeNodeWithNext(3);
var node4 = new TreeNodeWithNext(4);
var node5 = new TreeNodeWithNext(5);
var node6 = new TreeNodeWithNext(6);
var node7 = new TreeNodeWithNext(7);
root.Left = node2;
root.Right = node3;
node2.Left = node4;
node2.Right = node5;
node3.Left = node6;
node3.Right = node7;
ConnectAtSameLevel(root);
Console.ReadLine();
}
