public TreeNodeWithParent(int data)
{
Data = data;
Left = null;
Right = null;
Parent = null;
}
public static TreeNodeWithParent GetInOrderSuccessor(TreeNodeWithParent node)
{
if (node == null)
{
return(node);
}
if (node.RightNode != null)
{
return(GetLeftMostChild(node.LeftNode));
}
else
{
TreeNodeWithParent q = node;
TreeNodeWithParent x = q.ParentNode;
//Go up until we're on left instead of right
// We know that we change from left to root when the left is the same as q.
while (x != null && x.LeftNode != q)
{
q = x;
x = x.ParentNode;
}
return(x);
}
}
public static TreeNodeWithParent <int> LCA(TreeNodeWithParent <int> node0, TreeNodeWithParent <int> node1)
{
var n0Depth = GetDepth(node0);
var n1Depth = GetDepth(node1);
if (n1Depth > n0Depth)
{
var temp = node0;
node0 = node1;
node1 = temp;
}
var depthDiff = Math.Abs(n0Depth - n1Depth);
while (depthDiff-- > 0)
{
node0 = node0.Parent;
}
while (node0 != node1)
{
node0 = node0.Parent;
node1 = node1.Parent;
}
return(node0);
}
static void Main(string[] args)
{
TreeNodeWithParent root = new TreeNodeWithParent(1);
var node2 = new TreeNodeWithParent(2);
var node3 = new TreeNodeWithParent(3);
var node4 = new TreeNodeWithParent(4);
var node5 = new TreeNodeWithParent(5);
var node6 = new TreeNodeWithParent(6);
var node7 = new TreeNodeWithParent(7);
root.Left = node2;
root.Right = node3;
node2.Left = node4;
node2.Right = node5;
node2.Parent = root;
node3.Left = node6;
node3.Right = node7;
node2.Parent = root;
node4.Parent = node2;
node5.Parent = node2;
node6.Parent = node3;
node7.Parent = node3;
Console.Write(InOrderSuccessor(node2).Data);
Console.ReadLine();
}
private static TreeNodeWithParent LeftMostChild(TreeNodeWithParent root)
{
TreeNodeWithParent current = root;
while (current.Left != null)
{
current = current.Left;
}
return(current);
}
private static int GetDepth(TreeNodeWithParent <int> node)
{
var depth = 0;
while (node.Parent != null)
{
node = node.Parent;
depth++;
}
return(depth);
}
private static TreeNodeWithParent GetLeftMostChild(TreeNodeWithParent node)
{
if (node == null)
{
return(null);
}
while (node.LeftNode != null)
{
node = node.LeftNode;
}
return(node);
}
private static TreeNodeWithParent InOrderSuccessor(TreeNodeWithParent node)
{
if (node == null)
{
return(null);
}
if (node.Right != null)
{
return(LeftMostChild(node.Right));
}
else
{
TreeNodeWithParent child = node;
TreeNodeWithParent parent = node.Parent;
while (parent != null && parent.Left != child)
{
child = parent;
parent = child.Parent;
}
return(parent);
}
}
