The Minimum Window Substring is a popular problem in computer science, especially in coding interviews. It combines string manipulation with efficient algorithms, making it both challenging and rewarding to solve. In this post, we’ll break down the problem and its key aspects to set a strong foundation before diving into…
Squares Of Sorted Array – 977. LeetCode
Imagine you have an array of numbers sorted in increasing order, but some numbers are negative. If you square each number, the result is not longer sorted because squaring a negative number makes it positive. Your task is to return a new array where the squares of the numbers are…
Invariants 101: The Golden Rule for Reliable Algorithms
Invariants are a powerful tool in programming. They’re conditions that always remain true at specific points in an algorithm, no matter what. Establishing invariants early in the problem-solving process helps you write correct, efficient, and easy-to-understand code. In this blog, we’ll cover how to quickly establish invariants, explain their benefits,…
Recurrence Relations Made Easy: A Beginner’s Guide to Algorithmic Thinking
Have you ever wondered how recursive algorithms solve complex problems by breaking them into smaller pieces? The answer lies in recurrence relations—the mathematical backbone of recursion and dynamic programming. Whether it’s calculating Fibonacci numbers, optimizing a game strategy, or solving a divide-and-conquer problem like Merge Sort, recurrence relations provide a…
Binary Search Tree Iterator – 173. LeetCode
The Binary Search Tree (BST) Iterator problem asks you to implement an iterator for a BST. This iterator must support operations to efficiently traverse the BST in inorder (left → root → right) order. The iterator needs to provide the next smallest element in the BST using the next() method…
Flatten Nested Iterator – 341. LeetCode
In the Flatten Nested Iterator problem, you’re given a complex data structure that contains integers or nested lists of integers (like an onion with multiple layers). Your task is to design an iterator that can “flatten” this structure so you can iterate through the integers as if they were in…
Isomorphic Strings – 205. LeetCode
In simple terms, two strings are isomorphic if the characters in one string can be replaced to get the other string. Each character must map to exactly one character, and no two characters can map to the same character. For example: The challenge is to determine whether two given strings…
Intersection of Two Arrays – 349. LeetCode
The Intersection of Two Arrays problem asks you to find the unique elements that appear in both arrays. Imagine two groups of people; this task is like finding out who belongs to both groups. The challenge is to do this efficiently, especially when the arrays are large. The goal is…
Lowest Common Ancestor of a Binary Search Tree – 235. LeetCode
Imagine you’re navigating a family tree and need to find the closest common ancestor of two family members. The Lowest Common Ancestor (LCA) in a Binary Search Tree (BST) is the “earliest” node in the tree that is an ancestor of two given nodes. This concept is useful in systems…
Balanced Binary Tree – 110. LeetCode
Balancing a binary tree is a fundamental concept in computer science, especially in data structure optimization. The Balanced Binary Tree problem asks you to determine whether a given binary tree is height-balanced, which means it satisfies specific criteria for symmetry and efficiency. Let’s dive into the problem and break it…
