In this article, we will explore how to find the longest common prefix among a given set of strings using two different approaches in Java. We will first discuss an approach that compares all strings directly to find the longest prefix and then move to a word-by-word matching approach.  Problem Statement We are given a set of strings and we have to find the common prefix among all of them. A prefix is a substring for a string that contains the zero index and could be of any length from 1 to a complete string. Input 1 string arr[] = ... Read More

Matrix consists of rows and columns to form a rectangular array. And circular rotations mean rotating the array's elements so that one rotation places the last element in the first position and the rest of the elements to the right. In this problem, we have given a matrix of n * n, and our task is to check if all rows of a matrix are circular rotations of each other then print “YES” otherwise print “NO”. Let's see examples with explanations below to understand the problem in a better way. Input 1 mat = [ [ 1, 5, 6], ... Read More

The characters used in an arrangement of number notation based on the pre-Roman Roman system is called Roman numerals. The letters M, D, C, L, X, V, and I stand for 1000, 500, 1000, 50, 10, 5, and 1, respectively, and will discuss all main symbols in the below section. In this problem, we are given a string of Roman numerals and our task is to convert Roman numerals to decimals in the range of 1 to 3999. Let’s see examples with explanations below to understand the problem in a better way. Input 1 str = "MCMIX" Output 1 1909 ... Read More

The final keyword in Java may be employed to define a constant value as well as prevent a variable, method, or class from being changed or overridden. On the other side, immutability describes an object's characteristic of keeping a constant state across the course of its existence. The values of an object don't change after it is formed. Variables, methods, and classes are constrained by the "final" keyword, but immutability goes a step further by guaranteeing that the object's whole state is preserved. Let us learn the key differences between final vs immutability in this article. Final in Java ... Read More

Confounding Java questions stem from loops, multithreading, overloading, overriding, and more, making them challenging to navigate. Occasionally, seemingly simple questions confound us, leading to haphazard code instead of straightforward solutions. With analytical thinking, we can crack these questions even without prior knowledge. Join us as we explore tricky programs in Java. Methods Used Comments that work Named loops Method 1: Comments that work In the realm of programming, Java comments are textual statements within a program that hold no significance in terms of execution by the compiler or interpreter. The purpose behind incorporating comments into code is multifold. ... Read More

The Filter Design Pattern, also known as the Criteria Design Pattern, is a structural design pattern used by developers to filter objects based on different criteria. It enables decoupled filtering and logical operations by chaining multiple criteria into a single criterion. It provides two techniques for creating filters: filtering for the entire collection or filtering for a particular collection member. To apply criteria to a class, you can follow these steps: Create a class that requires filtering. Develop the criteria's interface. Implement concrete classes that meet the interface's requirements. Filter out certain objects by using a variety of criteria ... Read More

Rotation means we have to shift each character either in a forward direction or backward direction. Forward direction means right rotation (Or anticlockwise) and backward direction means left rotation (Or clockwise). In this problem, we have given a string of characters of size n and integer d. Here d is less than n. Our task is to print the left rotated string or right rotated string by d integer. Only the permutation of the current string changes, not the length or frequency of the characters in the given string. Input 1 str = “apple”, d = 2 Output 1 Left ... Read More

A feedback edge set in a graph refers to a set of edges that, when removed from the graph, eliminates all cycles or feedback loops. In other words, it is a subset of edges that, when deleted, transforms the original graph into a directed acyclic graph (DAG). A good feedback edge set is a feedback edge set that has the minimum possible number of edges. In this tutorial, we will learn to find a Good Feedback Edge Set in a Graph. Problem Statement Write a Java program that identifies and removes feedback edges in a graph to construct a Good ... Read More

In Java programming, there are scenarios where we need to extract individual digits from an integer for further manipulation or analysis. This tutorial will guide you through the process of extracting digits from a given integer using Java. Syntax while (num > 0) { int digit = num % 10; System.out.println(digit); num = num / 10; } The above is the syntax to extract digits from an integer in Java. We keep extracting the last digit by taking the remainder of the number with 10. We divide the number by 10 until it ... Read More

The Zhu-Takaoka algorithm is one of the best algorithms for pattern matching. It is developed using the combination of the Boyer-Moore and KMP string-matching algorithms. The Zhu-Takaoka algorithm utilizes the good character shift and bad character shift techniques to solve the problem. Problem statement − We have given two strings. We need to implement the Zhu-Takaoka algorithm for pattern matching. Sample Examples Input str = "PQRDPQRSSE"; patt = "PQRS"; Output 5 Explanation The ‘PQRS’ pattern exists at position 5. So, it prints 5. Input str = "PQRDPQRSSE"; patt = "PRQS"; Output -1 Explanation ... Read More