In this article, we will learn how to initialize a std::multiset with a custom comparator in C++. A multiset is similar to a set, except that it allows duplicate elements. It stores elements in a sorted order based on a comparison function. By default, elements are compared using the < (less-than) operator. However, with a custom comparator, we can define how elements should be compared. For example, if we define a custom comparator that sorts elements in descending order and insert the following elements into the multiset: Input: 3 12 5 8 1 7 9 4 6 Output: {12, 9, ... Read More

In this article, we will learn how to pass an array into a lambda function in C++. A lambda function is a small, anonymous function that doesn't have a name and can access variables from the surrounding code. Passing an array to a lambda function is a bit different from passing a single value because you need to define how the array will be handled inside the lambda. Let's see how to do that. Passing an Array into a Lambda Function We will cover four main methods to pass arrays into lambda functions in C++: ... Read More

In C++, a name conflict occurs when two or more identifiers, such as variables, functions, or classes, share the same name within the same scope. This creates ambiguity because the compiler may struggle to distinguish between them, leading to compilation errors. In this article, we will discuss name conflicts in C++ and also ways to resolve them, ensuring your code remains clear and error-free. Name Conflict Error in C++ Name conflicts typically occur when the same name is used for different variables, functions, or classes in conflicting or overlapping scopes, or when they are declared globally or within the ... Read More

In this article, we'll discuss the problem of finding the longest prefix in a string that has the highest frequency (appears most often) across the string. We'll break it down step-by-step and show how to efficiently solve this problem. Given a string, we need to find the longest prefix (the starting sequence) that appears most often in the string. A prefix is simply a substring that begins at the start of the string and includes one or more characters. Let's understand with an example. For the string 'abcabc', the prefixes are: a ... Read More

In this article, we will learn how to reduce a given array by replacing all subarrays with values less than a given number K by their sum. This process simplifies the array by merging smaller values. Given an array of integers and a value K, we need to find all contiguous subarrays whose values are less than K and replace them with their sum. After performing this reduction, the resulting array will have fewer elements, as the smaller subarrays will be combined into one. Let's consider an example. Given the array: [1, 2, 3, 5, 1, 4, 6, ... Read More

There are a total of 365 days in a normal year and 366 days in a leap year. In this article, we are going to learn how we can find the number of days in a month of a given particular year. Here, we will learn about different approaches for calculating the number of days in a given month using C++. How to Find the Number of Days in a Given Month? There are a total of 12 months in a year. The number of days in a given month from 1 to 12 in a given leap or non-leap ... Read More

In this article, we will learn how to deallocate a 2D array in C++. A 2D array is an array of arrays, where each element points to another array. When you dynamically allocate a 2D array, memory is reserved for each row and the main array on the heap. Deallocating memory means freeing the memory that was previously allocated for the 2D array so it can be reused. In C++, this involves deleting each row first and then deleting the main array. Deallocating a 2D Array in C++ In C++, a 2D array can be dynamically allocated ... Read More

In this article, we will explain how to find the greatest divisor that divides all the natural numbers in a given range [L, R]. The task is to identify the largest number that can divide every number between L and R, including both L and R. For example, in the range [6, 9] (which includes 6, 7, 8, and 9), the GCD is 1 because no number greater than 1 divides all of them. Now, let's go through the steps to solve this problem. Approach to Solve the Problem To solve this problem, we can follow these steps: ... Read More

In this article, we will discuss how to create a C++ program to generate the mirror image of a matrix across its diagonal. The diagonal mirror of a matrix means that we swap the elements at symmetric positions with respect to the diagonal. Let's break down the problem step by step and then look at the code that solves this problem. Understanding the Problem For any given matrix, the mirror image across the diagonal means that the element at position (i, j) will be swapped with the element at position (j, i). This operation is also known as transposing ... Read More

In this article, we will learn how to count pairs of numbers from a given array where the bitwise AND of the two numbers is greater than the bitwise XOR. Bitwise operations work on the individual bits of numbers. The AND operation results in 1 only when both bits are 1, while XOR gives 1 when the bits are different. Given an array of integers, we need to count how many pairs (i, j) exist such that the bitwise AND of the pair is greater than the bitwise XOR. In other words, for each pair of elements in the ... Read More