Ankit Kumar Mishra - LearnYard - Free Programming & DSA Blogs

Number of Atoms Solution In C++/Java/Python/JS

Problem Given a string formula representing a chemical formula, return the count of each atom. The atomic element always starts with an uppercase character, then zero or more lowercase letters, representing the name. One or more digits representing that element's count may follow if the count is greater

Perfect Rectangle Solution In C++/Java/Python/JS

Given an array rectangles where rectangles[i] = [xi, yi, ai, bi] represents an axis-aligned rectangle. The bottom-left point of the rectangle is (xi, yi) and the top-right point of it is (ai, bi). Return true if all the rectangles together form an exact cover of a rectangular region. Example Input:

Prefix Sum

Number of Flowers in Full Bloom Solution In C++/Java/Python/JS

Problem Description You are given a 0-indexed 2D integer array flowers, where flowers[i] = [start i, end i] means the ith flower will be in full bloom from start i to end i (inclusive). You are also given a 0-indexed integer array people of size n, where people[i] is

Find the AP/GP/HP Solution In C++/Java/Python/JS

When preparing for DSA interviews, we often come across number sequences. Three common types are: * Arithmetic Progression (AP) – where the difference between consecutive terms is constant. * Geometric Progression (GP) – where the ratio between consecutive terms is constant. * Harmonic Progression (HP) – where the reciprocals of the terms form an AP. Understanding

Implement Power function (pow(x,n)) question description

Implement Power Function (pow(x,n)) Solution in C++/Java/Python/JS

Description Implement pow(x,n), which calculates x raised to the power n (i.e., xn). Examples Input: x = 2.00000, n = 10 Output: 1024.00000 Input: x = 2.10000, n = 3 Output: 9.26100 Input: x = 2.00000, n = -2 Output: 0.25000 Explanation: 2-2 = 1/22 = 1/4

Minimize Maximum of Array Solution In C++/Java/Python/JS

Problem Description You are given a 0-indexed array nums comprising of n non-negative integers. In one operation, you must: Choose an integer i such that 1 <= i < n and nums[i] > 0. Decrease nums[i] by 1. Increase nums[i - 1] by 1. Return the minimum

Maximum Bags With Full Capacity of Rocks Solution In C++/Java/Python/JS

Problem Description You have n bags numbered from 0 to n - 1. You are given two 0-indexed integer arrays capacity and rocks. The ith bag can hold a maximum of capacity[i] rocks and currently contains rocks[i] rocks. You are also given an integer additionalRocks, the number of

[C++] OOPs - Exception Handling

Picture this: you’re a software engineer working on a banking application, and you’ve been tasked with building a feature that allows users to withdraw money from their accounts. The app is up and running, and it’s pretty smooth—users can check balances, make transfers, and even withdraw

[C++] OOPs - Templates and File Handling

Suppose you and I sit together, and I tell you — "Hey, let’s build a magical LEGO machine. It should be able to assemble a car today, a spaceship tomorrow, and maybe even a castle the day after!" Wouldn’t that be super cool? One machine — doing different

[C++] OOPs - Interfaces

Declaring an Interface in C++ (and the Magic of Abstraction) Let’s Begin: Why Hide the Details? Imagine you walk into a coffee shop. You say, "One cappuccino, please." The barista smiles, taps some buttons on a fancy machine, and voilà! your coffee appears. Now, think about this:

[C++] OOPs - Abstraction

C++ Abstraction: Hiding the Mess, Showing the Magic Why Do We Need Abstraction? Let’s start with a question: When you use a microwave, do you ever think about how it heats food internally? Do you worry about the electromagnetic waves, the circuit boards, or the power transformer inside? No,

[C++] OOPs - Encapsulation

Opening Scene: The Locked Room (Real-World Analogy) * Introduce the "locked room" story (your draft is already great — start with that!) * Big Question: Why do we lock certain rooms or items? What happens if we don't? * Relate to programming: We have “important rooms” in our code too

[C++] OOPs - Inheritance

What is Inheritance in C++? "Hey, suppose we have a general concept called 'Vehicle'. Now, can a Car be considered a type of Vehicle?" "Yeah! A car is definitely a vehicle." Exactly! Similarly, a bike or a bus are also types of vehicles, right?

[C++] OOPs - Operator and Function Overloading

Let's dive into this fascinating world of Operator and Function Overloading in C++ OOP, but we'll take it step by step and approach it as though we're learning together. This process should feel more like a friendly conversation than a lecture, so let'

[C++] OOPs - Polymorphism

What is Polymorphism in C++? Let’s Discover It Together Hey there! So you’ve heard this big word—polymorphism—and you’re wondering, “What’s the deal with that?” Don’t worry—we’re going to figure it out together. Let’s not dump a textbook definition right away.

[C++] OOPs - Pointers to Classes, this Pointer, Static Members and Class

The Curious Case of this Pointer "What happens when we call a function on an object? How does the object know it's itself?" Let’s imagine we both work in a factory. Every machine is identical but has its own serial number. When a machine processes

[C++] OOPs - Constructor and Destructor, Friend and Inline Functions

Hey! So, have you ever wondered how we prepare something the moment we create it? Let’s say we’re ordering coffee from an app. The moment we hit the order button, it immediately sets the coffee size, milk type, sugar count—everything based on our preferences. Now, what if

[C++] OOPs - Classes and Objects and Access Specifiers

Hey, have you ever wondered why C++ made such a big deal about "classes" and "objects"? I mean, why did we need them at all when C already had structs and functions? That’s exactly what I was thinking! Like, we already had ways to organize

[C++] OOPs - Introduction to Object Oriented Programming

Let's Talk About Object-Oriented Programming (OOP) in C++ Hey there! So you've just stepped into the world of C++, and suddenly people are throwing around big words like Object-Oriented Programming, encapsulation, polymorphism... and you’re like, “Wait, what did I sign up for?” Don’t worry

Simplify Path Solution In C++/Python/Java/JS

Simplify Path Problem Statement You are given an absolute path for a Unix-style file system, which always begins with a slash '/'. Your task is to transform this absolute path into its simplified canonical path. The rules of a Unix-style file system are as follows: 1. A single period

Minimum Seconds to Equalize a Circular Array Solution In C++/Java/Python/JS

Problem Description There are two mice and n different types of cheese, each type of cheese should be eaten by exactly one mouse. A point of the cheese with index i (0-indexed) is: reward1[i] if the first mouse eats it. reward2[i] if the second mouse eats it. You

Shortest Distance to a Character Solution Code in C++/Java/Python/JavaScript

Problem Given a string s and a character c that occurs in s, return an array of integers answer where answer.length == s.length and answer[i] is the distance from index i to the closest occurrence of character c in s. The distance between two indices i and j

Lexicographically Smallest Palindrome Solution Code in C++/Java/Python/JavaScript

Problem You are given a string s consisting of lowercase English letters, and you are allowed to perform operations on it. In one operation, you can replace a character in s with another lowercase English letter. Your task is to make s a palindrome with the minimum number of operations

Partition Array According to Given Pivot Solution Code in C++/Python/Java/JS

Problem You are given a 0-indexed integer array nums and an integer pivot. Rearrange nums such that the following conditions are satisfied: Every element less than pivot appears before every element greater than pivot. Every element equal to pivot appears in between the elements less than and greater than pivot.

Deletion at Xth Position

Continuing from insertion, deletion is another essential operation in problem-solving that helps us remove irrelevant, outdated, or specific elements from a dataset while preserving its structure. Whether it's removing a completed task from a to-do list, eliminating a player from a game leaderboard, or deleting an entry from