Program to Search a Node in a Binary Tree

Q. Program to search a node in a Binary Tree.

Trees are the non-linear data structure that stores data hierarchically. The tree is a collection of elements called nodes. Nodes are connected through edges and contain data. The first node of the tree is called Root. Each node may or may not have children node. The node which doesn’t have any child node is called leaf.

The binary tree is another kind of tree data structure in which each node can have at most two children. That is, each node in the binary tree will have data, left child and right child.

Program to search a node in a Binary Tree

Above diagram represents a binary tree in which 1 represent the root node of the tree. Node 2 has 4 as its left child and Node 3 has 5 as its left child and 6 as its right child. Nodes 4,5 and 6 are leaf nodes as they don?t have any child node.

Explanation

In this program, we will search a particular value in the binary tree. If it is present, print the message “Element is present in the binary tree” else print the message “Element is not present in the binary tree”. In a nutshell, we will first compare data of root with data of node to be searched. If the match is found, set the flag to true. Else, search the node in left subtree and then in the right subtree.

Algorithm

Define Node class which has three attributes namely: data left and right. Here, left represents the left child of the node and right represents the right child of the node.
When a node is created, data will pass to data attribute of the node and both left and right will be set to null.
Define another class which has two attribute root and flag.
1. Root represents the root node of the tree and initializes it to null.
2. The Flag will be used to check whether the given node is present in the tree or not. Initially, it will be set to false.
searchNode() will search for a particular node in the binary tree:
1. It checks whether the root is null, which means the tree is empty.
2. If the tree is not empty, it will compare temp?s data with value. If they are equal, it will set the flag to true and return.
3. Traverse left subtree by calling searchNode() recursively and check whether the value is present in left subtree.
4. Traverse right subtree by calling searchNode() recursively and check whether the value is present in the right subtree.

Solution

Python

  #Represent a node of binary tree  class Node:      def __init__(self,data):          #Assign data to the new node, set left and right children to None          self.data = data;          self.left = None;          self.right = None;     class SearchBinaryTree:      def __init__(self):          #Represent the root of binary tree          self.root = None;          self.flag = False;            #searchNode() will search for the particular node in the binary tree      def searchNode(self, temp, value):          #Check whether tree is empty          if(self.root == None):              print(“Tree is empty”);                    else:              #If value is found in the given binary tree then, set the flag to true              if(temp.data == value):                  self.flag = True;                  return;                            #Search in left subtree              if(self.flag == False and temp.left != None):                  self.searchNode(temp.left, value);                            #Search in right subtree              if(self.flag == False and temp.right != None):                  self.searchNode(temp.right, value);     bt = SearchBinaryTree();  #Add nodes to the binary tree  bt.root = Node(1);  bt.root.left = Node(2);  bt.root.right = Node(3);  bt.root.left.left = Node(4);  bt.root.right.left = Node(5);  bt.root.right.right = Node(6);            #Search for node 5 in the binary tree  bt.searchNode(bt.root, 5);     if(bt.flag):      print(“Element is present in the binary tree”);  else:      print(“Element is not present in the binary tree”);  

Output:

Element is present in the binary tree

C

  #include <stdio.h>  #include <stdbool.h>  #include <stdlib.h>     //Represent a node of binary tree  struct node{      int data;      struct node *left;      struct node *right;  };     //Represent the root of binary tree  struct node *root = NULL;     static bool flag = false;     //createNode() will create a new node  struct node* createNode(int data){      //Create a new node      struct node *newNode = (struct node*)malloc(sizeof(struct node));      //Assign data to newNode, set left and right children to NULL      newNode->data = data;      newNode->left = NULL;      newNode->right = NULL;            return newNode;  }     //searchNode() will search for the particular node in the binary tree  void searchNode(struct node *temp, int value){      //Check whether tree is empty      if(root == NULL){          printf(“Tree is emptyn”);      }      else{          //If value is found in the given binary tree then, set the flag to true          if(temp->data == value){              flag = true;               return;          }          //Search in left subtree          if(flag == false && temp->left != NULL){          searchNode(temp->left, value);          }          //Search in right subtree          if(flag == false && temp->right != NULL){          searchNode(temp->right, value);          }      }  }     int main()  {      //Add nodes to the binary tree      root = createNode(1);      root->left = createNode(2);      root->right = createNode(3);      root->left->left = createNode(4);      root->right->left = createNode(5);      root->right->right = createNode(6);                //Search for node 5 in the binary tree      searchNode(root, 5);            if(flag)          printf(“Element is present in the binary tree”);      else          printf(“Element is not present in the binary tree”);      return 0;  }  

Output:

Element is present in the binary tree

JAVA

  public class SearchBinaryTree {                //Represent a node of binary tree        public static class Node{          int data;          Node left;          Node right;                    public Node(int data){            //Assign data to the new node, set left and right children to null            this.data = data;            this.left = null;            this.right = null;          }        }                //Represent the root of binary tree        public Node root;                public static boolean flag = false;                public SearchBinaryTree(){          root = null;        }                //searchNode() will search for the particular node in the binary tree        public void searchNode(Node temp, int value){          //Check whether tree is empty          if(root == null){            System.out.println(“Tree is empty”);          }          else{            //If value is found in the given binary tree then, set the flag to true            if(temp.data == value){              flag = true;                 return;            }            //Search in left subtree            if(flag == false && temp.left != null){               searchNode(temp.left, value);            }            //Search in right subtree            if(flag == false && temp.right != null){               searchNode(temp.right, value);            }          }        }                public static void main(String[] args) {                   SearchBinaryTree bt = new SearchBinaryTree();          //Add nodes to the binary tree          bt.root = new Node(1);          bt.root.left = new Node(2);          bt.root.right = new Node(3);          bt.root.left.left = new Node(4);          bt.root.right.left = new Node(5);          bt.root.right.right = new Node(6);                    //Search for node 5 in the binary tree             bt.searchNode(bt.root, 5);                    if(flag)            System.out.println(“Element is present in the binary tree”);          else            System.out.println(“Element is not present in the binary tree”);                }      }  

Output:

Element is present in the binary tree

C#

  using System;   namespace Tree   {                           public class Program      {          //Represent a node of binary tree          public class Node<T>{              public T data;              public Node<T> left;              public Node<T> right;                            public Node(T data) {                  //Assign data to the new node, set left and right children to null                  this.data = data;                  this.left = null;                  this.right = null;              }          }                    public class SearchBinaryTree<T>{              //Represent the root of binary tree              public Node<T> root;                 public static Boolean flag = false;                 public SearchBinaryTree(){                  root = null;              }                        //searchNode() will search for the particular node in the binary tree              public void searchNode(Node<T> temp, T value){                  //Check whether tree is empty                  if(root == null){                    Console.WriteLine(“Tree is empty”);                  }                  else{                      //If value is found in the given binary tree then, set the flag to true                      if(temp.data.Equals(value)){                          flag = true;                          return;                      }                      //Search in left subtree                      if(flag == false && temp.left != null){                          searchNode(temp.left, value);                      }                      //Search in right subtree                      if(flag == false && temp.right != null){                           searchNode(temp.right, value);                      }                  }              }          }                    public static void Main()          {              SearchBinaryTree<int> bt = new SearchBinaryTree<int>();              //Add nodes to the binary tree              bt.root = new Node<int>(1);              bt.root.left = new Node<int>(2);              bt.root.right = new Node<int>(3);              bt.root.left.left = new Node<int>(4);              bt.root.right.left = new Node<int>(5);              bt.root.right.right = new Node<int>(6);                 //Search for node 5 in the binary tree              bt.searchNode(bt.root, 5);                 if(SearchBinaryTree<int>.flag)                Console.WriteLine(“Element is present in the binary tree”);              else                Console.WriteLine(“Element is not present in the binary tree”);          }          }  }  

Output:

Element is present in the binary tree

PHP

  <!DOCTYPE html>  <html>  <body>  <?php  //Represent a node of binary tree  class Node{      public $data;      public $left;      public $right;            function __construct($data){          //Assign data to the new node, set left and right children to NULL          $this->data = $data;          $this->left = NULL;          $this->right = NULL;      }  }  class SearchBinaryTree{      //Represent the root of binary tree      public $root;      public $flag;      function __construct(){          $this->root = NULL;          $this->flag = false;      }            //searchNode() will search for the particular node in the binary tree      function searchNode($temp, $value){          //Check whether tree is empty          if($this->root == NULL){            echo “Tree is empty<br>”;          }          else{            //If value is found in the given binary tree then, set the flag to true            if($temp->data == $value){                $this->flag = true;                return;            }            //Search in left subtree            if($this->flag == false && $temp->left != NULL){                $this->searchNode($temp->left, $value);            }            //Search in right subtree            if($this->flag == false && $temp->right != NULL){                $this->searchNode($temp->right, $value);            }          }      }  }  $bt = new SearchBinaryTree();  //Add nodes to the binary tree  $bt->root = new Node(1);  $bt->root->left = new Node(2);  $bt->root->right = new Node(3);  $bt->root->left->left = new Node(4);  $bt->root->right->left = new Node(5);  $bt->root->right->right = new Node(6);     //Search for node 5 in the binary tree  $bt->searchNode($bt->root, 5);     if($bt->flag)      echo “Element is present in the binary tree”;  else      echo “Element is not present in the binary tree”;        ?>  </body>  </html>  

Output:

Element is present in the binary tree

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Q. Program to search a node in a Binary Tree.

Explanation

Algorithm

Solution

Python

C

JAVA

C#

PHP

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