Trees can have any number of children, but the simplest and most common type of tree is a binary tree, where each node has at most two child nodes (called left child and right child). In other words, a node in a binary tree can have 0 or 1 or 2 child nodes.

The client-server architecture is a distributed application framework consisting of clients and servers in which the server hosts, manages, and delivers the client’s services. Here clients are connected to a central server, and they communicate over a network or internet connection through a computer network.

Given the root of a binary tree, write a program to check whether it is a valid binary search tree (BST) or not. A BST is valid if all nodes in the left subtree have values less than the node’s value, all nodes in the right subtree have values greater than the node’s value, and both left and right subtrees are also binary search trees.

Regular expression is an expression that holds a defined search pattern to extract the pattern-specific strings. Today, RE are available for almost every high-level programming language and as data scientists or NLP engineers, we should know the basics of regular expressions and when to use them.

Given two strings str1 and str2 of size m and n, write a program to check whether the two strings are an anagram of each other or not. A string str1 is an anagram of str2 if the characters of str1 can be rearranged to form str2.

Inheritance is one of the core principles of object-oriented programming (OOP), which help us derive a class from another class or a hierarchy of classes that share a set of attributes and methods. In other words, it is a relationship between a superclass (a more generalised class) and a subclass (a more specialised class), where the subclass inherits data and behavior from the superclass.