Subsets II | Backtracking
leetcode.com Problem Statement Given an integer array nums that may contain duplicates, return all possible subsets (the power set). The solution must…
Programming
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# 👽 Verifying an Alien Dictionary (LeetCode 953)
Imagine you're interviewing on another planet. 🌎➡️🛸 The aliens use the same English lowercase letters ( a-z ), but their alphabet order is completely …
🚀 LeetCode 329: Longest Increasing Path in a Matrix (DFS + Memoization) | Easy Explanation
One of the most common mistakes while solving graph problems on matrices is accidentally turning an O(m*n) problem into exponential recursion 😅 This p…
[System Design] Ride-Hailing Dispatch Algorithm: How Uber DISCO & Grab DispatchGym Match Drivers
Every time you tap "Book Ride," a system makes dozens of decisions in under two seconds: Which driver? What route? What's the real ETA? This article b…
Surprise Over Age of Fundamental Algorithms: Modern AI Excluded from Standard University Courses
Introduction: The Timeless Nature of Algorithms When you crack open a standard Data Structures and Algorithms textbook, it’s easy to assume the conten…
Sliding Window: The Force Awakens – Detect the Pattern and Never Get Stuck Again
The Quest Begins (The “Why”) I still remember the first time I faced a “minimum size subarray sum” question in an interview. The problem stared back a…
Max Consecutive Ones
Problem Statement Given a binary array nums , return the maximum number of consecutive 1's present in the array. Example Input: nums = [1,1,0,1,1,1] O…
Remove Duplicates from Sorted Array
Problem Statement Given a sorted integer array nums , remove the duplicates in-place such that each unique element appears only once. Return the numbe…
Ray Tracing
Honestly, the way dedicated hardware and software engineering have teamed up has totally changed the game for developers making worlds look real. Inst…
🚀 BFS: The Jedi Mind Trick for Graph Traversal (Why It’s More Than Just a Queue)
The Quest Begins (The “Why”) I still remember the first time I stared at a whiteboard interview question that asked for the shortest number of moves a…
I am a 16-year-old dev and built a Heuristic Algorithm for the Subset Sum Problem approximating O(\log N). Need your feedback!
First, peace be upon you. I am a 16-year-old programmer, and I tried to solve the well-known Subset Sum problem. Before starting the definition, the s…
Why You Keep Failing Dynamic Programming Problems (And How to Actually Fix It)
TL;DR: Dynamic programming is the topic most developers struggle with longest, and the reason is almost always the same: they are trying to memorize s…
Three decisions behind a music-to-curator matching score
I build OTONAMI , a pitch platform that connects independent artists with music curators — playlist editors, radio DJs, bloggers, label scouts. At its…
Linked List Cycle II
leetcode.com Problem Statement Given the head of a linked list, return the node where the cycle begins. If there is no cycle, return null . You are no…
Palindrome Linked List
leetcode.com Problem Statement Given the head of a singly linked list, return true if the linked list is a palindrome and false otherwise. Example 1 I…
The Math Behind O(log n): Binary Search, log , and Why Halving Wins
You have read O(log n) a hundred times. Binary search is O(log n) . A balanced BST lookup is O(log n) . Heap insert is O(log n) . We nod along — log n…
How QR Code Logo Embedding Works (Without Breaking Scannability)
You've seen QR codes with logos in the center. Maybe a Starbucks QR with their siren, or a brand's QR with their logo stamped dead center. How does th…
Reverse Nodes in K-Group
leetcode.com Among all Linked List problems, Reverse Nodes in K-Group is one of the most challenging and interview-favorite questions because it combi…
Linked List Cycle Detection
leetcode.com Cycle detection is one of the most classic Linked List interview problems. At first, it may look like we need extra memory to track visit…
I Got Bored of LeetCode, so I Built a Coding RPG
https://dsa-life-simulator-frontend.vercel.app"I made a free tool to make DSA practice feel like an RPG — would like feedback from this community"Been…
How Constraints Changed the Way I Think About Algorithms
Over the past couple of years, I've spent a lot of time preparing for software engineering interviews. Like many developers, I started my Data Structu…
Delete Node in a Linked List
Problem Link - https://leetcode.com/problems/delete-node-in-a-linked-list/ This is one of those interview questions that looks impossible at first. No…
Hashing in Distributed Systems: A Complete Guide to Algorithms, Best Practices, and Real-World Applications
Have you ever wondered how Discord keeps your channel messages available even when a server goes down? Or how Amazon DynamoDB serves petabytes of data…
Deutsch Algorithm Revisited: Quantum vs Classical Implementation in Qiskit
In the previous post on the Deutsch algorithm , we covered the theory. Here we implement both the classical and quantum approaches in Qiskit so the qu…
Deutsch's Algorithm in Quantum Computing: The 4 Cases
Deutsch's Algorithm determines whether a function f(x) is constant or balanced using only a single query. Before getting to the quantum circuit, it he…
Reverse Pairs
Given an integer array nums , return the number of reverse pairs. A reverse pair is defined as: i < j && nums [ i ] > 2 * nums [ j ] Bru…
A Practical Guide to the ROS Navigation Stack: Core Components & Tuning
With rapid advances in robotics, autonomous navigation has become essential for mobile robots. The ROS Navigation Stack is the de facto open-source fr…
Segment Trees: The “Divide‑and‑Conquer” Trick That Actually Makes Sense
Segment Trees: The “Divide‑and‑Conquer” Trick That Actually Makes Sense Quick context (why you're writing this) I remember the first time I saw a segm…
The Fastest Set Is Often Not a Set: 4050 Duplicate-Detection Benchmarks
Duplicate detection looks solved: keep a hash set, skip what you have already seen. A benchmark suite of 4050 measurements across 480 workloads says t…
DSA vs. Real-World Coding Interviews — and Where Does AI Leave Us?
For a long time, I have come across the debate on the right way to vet technical candidates: should interviews focus on Data Structures & Algorith…