Binary Search Tree insert with Parent Pointer | Java program to demonstrate insert operation in binary search tree with parent pointer ; Node structure ; A utility function to create a new BST Node ; A utility function to do inorder traversal of BST ; A utility function to insert a new Node with given key in BST ; If the tree is empty , return a new Node ; Otherwise , recur down the tree ; Set parent of root of left subtree ; Set parent of root of right subtree ; return the ( unchanged ) Node pointer ; Driver Program to test above functions ; Let us create following BST 50 / \ 30 70 / \ / \ 20 40 60 80 ; print iNoder traversal of the BST
class GfG { static class Node { int key ; Node left , right , parent ; } static Node newNode ( int item ) { Node temp = new Node ( ) ; temp . key = item ; temp . left = null ; temp . right = null ; temp . parent = null ; return temp ; } static void inorder ( Node root ) { if ( root != null ) { inorder ( root . left ) ; System . out . print ( " Node ▁ : ▁ " + root . key + " ▁ , ▁ " ) ; if ( root . parent == null ) System . out . println ( " Parent ▁ : ▁ NULL " ) ; else System . out . println ( " Parent ▁ : ▁ " + root . parent . key ) ; inorder ( root . right ) ; } } static Node insert ( Node node , int key ) { if ( node == null ) return newNode ( key ) ; if ( key < node . key ) { Node lchild = insert ( node . left , key ) ; node . left = lchild ; lchild . parent = node ; } else if ( key > node . key ) { Node rchild = insert ( node . right , key ) ; node . right = rchild ; rchild . parent = node ; } return node ; } public static void main ( String [ ] args ) { Node root = null ; root = insert ( root , 50 ) ; insert ( root , 30 ) ; insert ( root , 20 ) ; insert ( root , 40 ) ; insert ( root , 70 ) ; insert ( root , 60 ) ; insert ( root , 80 ) ; inorder ( root ) ; } }