Programming Articles - Page 2292 of 3366

Constructors are special methods used to initialize objects, whereas methods are used to execute certain statements. Constructors and methods are both blocks of code inside a class, but they have different purposes. In this article we will learn about the main differences between a constructor and a method. What is a Constructor in Java? A constructor is a special method in Java that is automatically called when an object is instantiated. Constructors have the same name as the class and do not have a return type. Its main purpose is to set initial values to the newly created object. ... Read More

Scanner and BufferedReader classes are used to read input from an external system. Scanner is normally used when we know input is of type string or of primitive types, and BufferedReader is used to read text from character streams while buffering the characters for efficient reading of characters. What is Scanner Class? The Scanner class is included in the java.util package. It is mostly used when the data type of the input is already known. We commonly use it with data ty+pes like strings, integers, floats, and booleans. It has built-in methods like nextInt(), nextDouble(), and nextLine() that help ... Read More

Abstract class and concrete class are fundamental concepts of object oriented programming in Java. In this article, we will learn the differences between an abstract class and concrete class. What is an Abstract Class? An abstract class is a class that cannot be used to create objects. It can only be accessed using its subclasses. It can contain abstract methods, which are methods without a body. It acts as a blueprint for its subclasses. It can also contain concrete or regular methods. Example This example shows how to implement an abstract class in java: ... Read More

Problem statementGiven a binary matrix of N rows and M columns. The operation allowed on the matrix is to choose any index (x, y) and toggle all the elements between the rectangle having top-left as (0, 0) and bottom-right as (x-1, y-1). Toggling the element means changing 1 to 0 and 0 to 1. The task is to find minimum operations required to make set all the elements of the matrix i.e make all elements as 1.ExampleIf input matrix is {0, 0, 0, 1, 1}    {0, 0, 0, 1, 1}    {0, 0, 0, 1, 1}    {1, 1, ... Read More

Problem statementGiven a set of n integers, perform minimum number of operations (you can insert/delete elements into/from the set) to make the MEX of the set equal to x (that is given).Note − The MEX of a set of integers is the minimum non-negative integer that doesn’t exist in it. For example, the MEX of the set {0, 2, 4} is 1 and the MEX of the set {1, 2, 3} is 0ExampleIf n = 5 and x = 3 and array is {0, 4, 5, 6, 7} then we require minimum 2 operationsAlgorithmThe approach is to see that in ... Read More

Problem statementWe are given an array of n elements. The task is to make XOR of whole array 0. We can do following to achieve this.We can select any one of the element −After selecting element, we can either increment or decrement it by 1.We need to find the minimum number of increment/decrement operation required for the selected element to make the XOR sum of whole array zeroExampleIf arr[] = {2, 4, 7} then 1 operation is required −Select element 2Decrement it by 1Now array becomes {3, 4, 7} and its XOR is 0AlgorithmFind the XOR of whole arrayNow, suppose ... Read More

Problem statementGiven an array arr[] of positive numbers, find minimum number of sets in array which satisfy following property, A set can contain maximum two elements in it. The two elements need not to be contiguous.Sum of elements of set should be less than or equal to given Key. It may be assumed that given key is greater than or equal to the largest array element.ExampleIf arr[] = {1, 2, 3, 4} and k = 5 then following 2 pairs can be created −{1, 4} and {2, 3}AlgorithmSort the arrayBegin two pointers from two corners of the sorted array. If ... Read More

Problem statementGiven N questions and K options for each question, where 1

Problem statementGiven values of A and B, find the minimum positive integer value of X that can be achieved in the equation X = P*A + Q*B, Here P and Q can be zero or any positive or negative integer.ExampleIf A = 2 and B = 4 then answer will be 2.AlgorithmWe need to find P and Q such that P*A > P*B and P*A – P*B is minimum positive integer.This problem can be easily solved by calculating GCD of both numbers)Example#include using namespace std; int getGcd(int a, int b) {    if (a == 0) {     ... Read More

Problem statementYou are given an array of n integer and an integer K. Find the number of total unordered pairs {i, j} such that absolute value of |ai + aj – k| is minimal possible where i != j.ExampleIf arr[ ] = {0, 4, 6, 2, 4} and k = 7 then we can create following 5 pairs with minimal value as 1{0, 6}, {4, 2}, {4, 4}, {6, 2}, {2, 4}AlgorithmIterate over all possible pairs and for each pair we will check whether the value of (ai + aj – K) is smaller than our current smallest value of ... Read More