If you’ve ever faced a problem involving multiple sorted arrays or lists that need to be combined into one sorted result, you’ve encountered a k-way merge scenario. It’s an essential algorithmic technique, powering systems like search engines, data processing pipelines, and distributed databases. In this post, we’ll break down the…
Kth Largest Element in a Stream – 703. LeetCode
Imagine you are continuously receiving numbers in a stream, and you want to keep track of the Kth largest element at any given time. This means if you are given a number k, you need to find the k-th largest element among all the numbers you have received so far….
Minimum Window Substring – 76. LeetCode
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…
