450. Delete Node in a BST
Consider cases
1. No Child elements then delete the node
2. If one child element replace the current node with a child
3. If two children then either pick the largest in left subtree or smallest in right sub tree.
1. No Child elements then delete the node
2. If one child element replace the current node with a child
3. If two children then either pick the largest in left subtree or smallest in right sub tree.