In previous post, discussed about leaf node and total nodecount of BST. In this post, we will see how to delete a node from binary search tree.
There are three scenario which we may need to consider while deleting a node from Binary Tree.
1) If node has no child(i.e leaf node)
![Delete a node has no child]( "Delete a node has no child")
Example:--
3) If node has two children
BSTDeleteNode.java
Output :-
Printing node before delete,
4 6 8 10 16
Printing node after delete,
4 6 8 10
Related Post:--
1) Java Program to Count the number of nodes and leaf nodes of Binary Tree
2) Java Program to Reverse a Linked List using Recursion and Loops
3) How to Remove duplicates from ArrayList in Java
4) Java Program to Count Occurrence of Word in a Sentence
5) How to iterate the TreeMap in reverse order in Java
There are three scenario which we may need to consider while deleting a node from Binary Tree.
- If node has no child(i.e leaf node)
- If node has one child.
- If node has two children.
It is easy and straight forward, Just We need to search the node and make it null.
2) If node has one child
If node have one children then we need to connect parent of removed node directly to child of the removed node.
Example:-
![Delete a node have one child]( "Delete a node have one child")
3) If node has two children
It is somewhat complicated to delete the node. If it has two nodes, we need to connect parent of node to the leftmost node(minimum) of right sub tree or rightmost node(maximum) of left sub tree.
Example:--
![Delete two child of Binary Tree]( "Delete two child of Binary Tree")
Java Program to Delete the Node from a Binary Tree.
BSTDeleteNode.java
package com.test;
classNode{
Integer data;
Node leftChild;
Node rightChild;
publicNode(Integer data){
this.data= data;
leftChild =null;
rightChild =null;
}
}
publicclassBSTDeleteNode{
Node root;
Node deleteNode(Integer data){
returndeleteNode(root, data);
}
Node deleteNode(Node node, Integer data){
if(node ==null)
return node;
if(data < node.data){
node.leftChild= deleteNode(node.leftChild, data);
}elseif(data > node.data){
node.rightChild= deleteNode(node.rightChild, data);
}else{
//node with only one child or no child
if(node.leftChild==null){
return node.rightChild;
}elseif(node.rightChild==null){
return node.leftChild;
}
//node with two children, smallest in the right subtree
node.data= minValue(node.rightChild);
node.rightChild= deleteNode(node.rightChild, node.data);
}
return node;
}
intminValue(Node root){
int minv = root.data;
while(root.leftChild!=null){
minv = root.leftChild.data;
root = root.leftChild;
}
return minv;
}
/* To Print the given Node data
*/
voidinorderRec(){
inorderRec(root);
}
voidinorderRec(Node root){
if(root !=null){
inorderRec(root.leftChild);
System.out.print(root.data+"");
inorderRec(root.rightChild);
}
}
publicstaticvoidmain(String[] args){
BSTDeleteNode tree =new BSTDeleteNode();
tree.root=new Node(10);
tree.root.leftChild=new Node(6);
tree.root.rightChild=new Node(16);
tree.root.leftChild.leftChild=new Node(4);
tree.root.leftChild.rightChild=new Node(8);
System.out.println("Printing node before delete,");
tree.inorderRec();
tree.deleteNode(16); //delete node method
System.out.println("");
System.out.println("Printing node after delete,");
tree.inorderRec();
}
}
Output :-
Printing node before delete,
4 6 8 10 16
Printing node after delete,
4 6 8 10
Related Post:--
1) Java Program to Count the number of nodes and leaf nodes of Binary Tree
2) Java Program to Reverse a Linked List using Recursion and Loops
3) How to Remove duplicates from ArrayList in Java
4) Java Program to Count Occurrence of Word in a Sentence
5) How to iterate the TreeMap in reverse order in Java