public BinaryTree Remove(int value, BinaryTree parentNode = null)
{
// Average - O(log(N)) | O(1) Space
// Worst - O(N) time | O(1) Space
// First we find the node we want to remove
// Then remove it.
var currentNode = this;
while (currentNode != null)
{
if (value < currentNode.value)
{
parentNode = currentNode; // keep track of parent node
currentNode = currentNode.left;
}
else if (value > currentNode.value)
{
parentNode = currentNode;
currentNode = currentNode.right;
}
else
{
if (currentNode.left != null && currentNode.right != null)
{
// Here if node has 2 children nodes
currentNode.value = currentNode.right.getMinValue(); // set value to smallest value of right subtree
currentNode.right.Remove(currentNode.value, currentNode); // remove smallest value from where we got it
}
else if (parentNode == null)
{
if (currentNode.left != null)
{
currentNode.value = currentNode.left.value;
currentNode.right = currentNode.left.right;
currentNode.left = currentNode.left.left;
}
else if (currentNode.right != null)
{
currentNode.value = currentNode.right.value;
currentNode.left = currentNode.right.left;
currentNode.right = currentNode.right.right;
}
else
{
currentNode.value = 0;
}
}
else if (parentNode.left == currentNode)
{
if (currentNode.left != null)
{
parentNode.left = currentNode.left;
}
else
{
parentNode.left = currentNode.right;
}
}
else if (parentNode.right == currentNode)
{
if (currentNode.left != null)
{
parentNode.left = currentNode.right;
}
else
{
parentNode.right = currentNode.right;
}
}
break;
}
}
return(this);
}
public BinaryTree(int value)
{
this.value = value;
this.left = null;
this.right = null;
}
