The two pointer technique is one of the most common and powerful patterns used in competitive programming, data structures, and algorithms. It helps solve problems that involve searching, sorting, or traversing arrays, strings, or linked lists in an efficient way. Core At its core, the idea is simple, Instead of brute-forcing through every possible pair … Read more
Greedy algorithms are one of the most elegant problem-solving strategies in computer science. They are fast, intuitive, and often surprisingly effective—but only when applied to the right problems. This guide walks you through the recipe for designing greedy algorithms, the common proof techniques, and the classic patterns you must know. What Is a Greedy Algorithm? … Read more
A Queue is a linear data structure that follows the principle of First In, First Out (FIFO). Introduction A Queue is a linear data structure that follows the principle of First In, First Out (FIFO). This means that the first element inserted into the queue will be the first one to be removed — just … Read more
Tree traversals are one of the first things we learn in data structures — but they’re often taught only at a surface level: as different ways to “walk” a tree. What’s rarely emphasized is this: A Quick Refresher Given a binary tree, the three primary depth-first traversals are: Traversal Order Preorder Root → Left → … Read more
Check Same binary Tree Leet 100. Same Tree When we first read the “Same Tree” problem, we often think of comparing the traversal results — like inorder, preorder, or postorder — of both trees. That’s a natural and valid idea, but it’s not necessary or ideal in this case. Case 1 : Using one of … Read more
Design patterns are proven solutions to common problems that occur repeatedly in software design. They provide a shared vocabulary and standard practices that improve code readability, scalability, and maintainability. These patterns are not specific to any programming language but serve as guiding templates for solving architectural challenges in object-oriented systems. By studying and applying design … Read more
Competitive programming is not just about knowing programming syntax—it’s a blend of logic, speed, and mathematics. Mastering a few essential math tricks can drastically boost your problem-solving skills and efficiency. Let’s explore the most powerful and commonly used math techniques in competitive programming. Number of times a prime p exist in n! Example find no. … Read more
GCD and LCM is a foundational concept in number theory and widely used in areas such as simplifying fractions, cryptography, and solving Diophantine equations. GCD (Greatest Common Divisor) GCD of 12 and 18 So, the GCD is 6 Euclidean Algorithm for GCD This is an efficient method to find GCD: Code Euclidean Algorithm, Why it … Read more
A Binary Search Tree is a type of binary tree where each node follows a specific ordering property: the left child of a node contains a value less than the node’s value, and the right child contains a value greater than the node’s value. This property makes searching, insertion, and deletion efficient. Introduction A Binary … Read more
Automated testing is a crucial aspect of modern software development. It ensures code reliability, maintainability, and helps prevent regression bugs. In the Python ecosystem, Pytest stands out as one of the most powerful, flexible, and widely-used testing frameworks. What is Pytest? Pytest is a testing framework for Python that makes it easy to write simple … Read more