public static Tuple <NodeX, NodeX> ConvertTreeToDoubleLinkedList(TreeNode node)
{
if (node.left == null && node.right == null)
{
NodeX node1 = new NodeX(null, null, node.value);
return(Tuple.Create(node1, node1));
}
if (node.left != null && node.right == null)
{
var tuple = ConvertTreeToDoubleLinkedList(node.left);
NodeX root = new NodeX(null, null, node.value);
root.prev = tuple.Item2;
tuple.Item2.next = root;
return(Tuple.Create(tuple.Item1, root));
}
if (node.left == null && node.right != null)
{
var tuple = ConvertTreeToDoubleLinkedList(node.right);
NodeX root = new NodeX(null, null, node.value);
root.next = tuple.Item1;
tuple.Item1.prev = root;
return(Tuple.Create(root, tuple.Item2));
}
var leftTuple = ConvertTreeToDoubleLinkedList(node.left);
var rightTuple = ConvertTreeToDoubleLinkedList(node.right);
NodeX rootX = new NodeX(rightTuple.Item1, leftTuple.Item2, node.value);
rightTuple.Item1.prev = rootX;
leftTuple.Item2.next = rootX;
return(Tuple.Create(leftTuple.Item1, rightTuple.Item2));
}
public NodeX(NodeX next, NodeX prev, int value)
{
this.next = next;
this.prev = prev;
this.value = value;
}