public TreeNodeWithNext Connect(BinaryTree input)
{
TreeNodeWithNext root = input.ConvertToTreeNodeWithNext();
Connect(root);
return(root);
}
public static TreeNodeWithNext ConvertToTreeNodeWithNext(this BinaryTree root)
{
if (root != null)
{
TreeNodeWithNext newRoot = new TreeNodeWithNext(root.Value);
newRoot.Left = ConvertToTreeNodeWithNext(root.Left);
newRoot.Right = ConvertToTreeNodeWithNext(root.Right);
return(newRoot);
}
return(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 root)
{
if (root == null)
{
return;
}
if (root.Left == null && root.Right == null)
{
return;
}
root.Left.Next = root.Right;
if (root.Next != null)
{
root.Right.Next = root.Next.Left;
}
Connect(root.Left);
Connect(root.Right);
}
public static string SerializeTreeNodeWithNext(this TreeNodeWithNext root)
{
if (root == null)
{
return("{}");
}
StringBuilder sb = new StringBuilder();
sb.Append("{");
var currentLevel = root;
TreeNodeWithNext nextLevel = null;
while (currentLevel != null)
{
while (currentLevel != null)
{
if (nextLevel == null)
{
if (currentLevel.Left != null)
{
nextLevel = currentLevel.Left;
}
else if (currentLevel.Right != null)
{
nextLevel = currentLevel.Right;
}
}
sb.Append(currentLevel.Value + ",");
currentLevel = currentLevel.Next;
}
sb.Append("#,");
currentLevel = nextLevel;
nextLevel = null;
}
string result = sb.ToString();
return(result.TrimEnd(',') + "}");
}
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;
}
}
}
}