Preorder traversal

Preorder traversal: In preorder traversal root is visited first.

 Steps:

 1. Visit the root
2. Traverse the left subtree
3. Traverse the right subtree

 Code:

 
void preOrder(Node root) {
    if(root==null)
        return;
    System.out.print(root.data+" ");
    preOrder(root.left);
    preOrder(root.right);

}


Illustration:






Preorder traversal of given tree is 1, 2, 3, 4, 5









 Visit the root





 Traverse the left subtree





  Traverse the right subtree





  Visit the root





  Traverse the left subtree





  Traverse the right subtree















































Comments











Post a Comment
























Popular posts from this blog









Tree traversals - Inorder Traversal




















Image







         A binary tree can be traversed in two ways.  i) Depth First Traversal: Inorder, preorder, postorder  ii) Breadth First Traversal: Level Order Traversal   Inorder traversal:         In inorder traversal root is visited in between left and right subtree traversals.   Steps:  1.  Traverse the left subtree  2.  Visit the root  3. Traverse the right subtree   Note: If binary search tree is traversed in inorder, the numbers will be sorted in ascending order.   Code:    void inOrder(Node root) {     if(root==null)         return;     inOrder(root.left);     System.out.print(root.data+" ");     inOrder(root.right);  }   Illustration:    Inorder traversal of given tree is 3, 5, 4, 7, 8    Consider the left subtree of 7 (since 7 is the root ,we always start our traversal from root)     Here we start form 5, the left subtree of 5 is 3. For 3 the left subtree is empty , So we visit the root. The right subtree of tree is also empty. At ...








Read more










Binary Search tree (Insertion)




















Image







    A tree in which every node can have a maximum of two children is called a binary tree.        A binary search tree is a binary tree in which every node has lower values in the left sub tree and higher values in the right sub tree.   Node of binary tree:   class Node{       int data;       Node left, right;       Node(int data){          this.data = data;          right = left = null;       }  }   BST - Insertion:    static Node Insert(Node root,int data) {       if( root == null ){             root = new Node(data);             return root;       }       if( data < root.data)              root.left = Insert(root.left,data);       else              root.right = Insert(root.rig...








Read more










Stack implementation using array




















Image







      Introduction:      Stack is a linear data structure which follows LIFO( Last In First Out ) order.      To represent stack consider books are placed in table for the teacher to correct. The note which is submitted last will be corrected first. The person who submits last is quite unlucky isn't it :P     Operations:   push: Inserts element at the top of the stack   pop: Removes element from the top of the stack     Stack implementation using array:     Code:        import java.util.*;   import java.lang.*;   import java.io.*;     class Stack   {       int SIZE = 10;       int arr[] = new int[SIZE];       int top = -1;              public int pop(){           if (top == -1){               System.out.println("stack is empty");               return 0;           }           int topelement ...








Read more