In this tutorial, i am going to discuss what is binary tree preorder traversal? How to implement binary tree preorder traversal with and without recursion.
Given the root of a binary tree, write a code to return the preorder traversal of its nodes’ values.
In this post, I am going to discuss a very famous interview problem validate binary search tree or in other words check if a binary tree is BST or not.
Given the root of a binary tree, We have to write a code to check if it is a binary search tree (BST) or not.
The property of a valid binary search tree (BST) is:
i) The left subtree of a node contains only nodes with keys less than the node’s key.
ii) The right subtree of a node contains only nodes with keys greater than the node’s key.
iii) Both the left and right subtrees must also be binary search trees.
For example –
Let’s discuss a problem add two numbers as lists and their java code.
Given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order, and each of their nodes contains a single digit. We have to write a code to add these two numbers and return the sum as a linked list.
For this problem, you may assume the two numbers do not contain any leading zero, except the number 0 itself.
For example –
Linked List 1 : 2 -> 4 -> 6 -> NULL
Linked List 2 : 5 -> 6 -> 4 -> NULL
Result : 7 -> 0 -> 1 -> 1 -> NULL
Explanation :
In this example first, we added 2 and 5 the result is 7. Then, 6 and 4 the result is 10, so we put 0 and take 1 as a carry. Then, we added 6, 4, and 1 (carry) the result is 11, so we put 1 and take 1 as a carry.