From the blog
By rakeshreddy512 | September 15, 2025
Leetcode - 23. Merge k Sorted Lists
When working with linked lists, a classic problem you’ll encounter is: “Given k sorted linked......
Leetcode - 427. Construct Quad Tree
QuadTrees are a fascinating data structure, often used in image compression, spatial indexing, and......
Leetcode - 148. Sort List
Sorting a linked list isn’t as straightforward as sorting an array. With arrays, we can do quick sort......
By rakeshreddy512 | August 31, 2025Backend Interview Prep Beyond LeetCode (For 3 Years Experience)
Most backend engineers spend months grinding LeetCode. But in reality, backend interviews are about......
By rakeshreddy512 | August 31, 2025Frontend Interview Prep Beyond LeetCode (For 3 Years Experience)
Most developers preparing for frontend interviews drown themselves in LeetCode. While data structures......
Leetcode - 108. Convert Sorted Array to Binary Search Tree
When you’re given a sorted array, you might be asked to convert it into a height-balanced binary......
Leetcode -79. Word Search
The Word Search problem is a classic interview question that tests recursion, grid traversal, and......
22. Generate Parentheses
Got it, Rakesh 🚀 Let’s turn this into a neat blog post. I’ll explain the problem, walk through the......
Leetcode - 52. N-Queens II
🏰 Solving the N-Queens Problem with Backtracking The N-Queens problem is a classic in......
Leetcode - 39. Combination Sum
The Combination Sum problem is a classic backtracking question from LeetCode (#39). We are......
46. Permutations
Understanding Permutations in JavaScript (Step by Step) Permutations are all the possible......
Leetcode - 77. Combinations
Problem Given two integers n and k, return all possible combinations of k numbers chosen......
Leetcode - 17. Letter Combinations of a Phone Number
Ever wondered how your phone predicts words when you’re typing on a numeric keypad? That’s exactly......
Leetcode - 212. Word Search II
Solving Word Search II with Trie and DFS Finding words in a 2D board may sound like a fun......
Leetcode - 211. Design Add and Search Words Data Structure
🔎 Word Dictionary with Wildcards — Trie + DFS Approach Imagine you’re building a search......
Leetcode - 208. Implement Trie (Prefix Tree)
✨ What is a Trie? A Trie (pronounced like "try") is a special type of tree used to store......
Leetcode - 127. Word Ladder
🔗 Solving the Word Ladder Problem Using BFS in JavaScript The Word Ladder problem is a......
Leetcode - 433. Minimum Genetic Mutation
🔍 Problem Overview Imagine you’re playing a game where you can mutate genes by changing......
Leetcode - 909. Snakes and Ladders
Approach We treat the Snakes and Ladders board as an unweighted graph: Each square = a......
Leetcode - 210. Course Schedule II
If you've ever tried stacking books in the correct order without violating any “pre-read” rule (e.g.,......
399. Evaluate Division
🔍 Problem Overview We are given equations like: a / b = 2.0 b / c = 3.0 Enter......
By rakeshreddy512 | July 14, 2025JavaScript Built-in Method Cheat Sheet
JavaScript Built-in Method Cheat Sheet Ever find yourself in the middle of a LeetCode......
Leetcode - 130. Surrounded Regions
🚀 Approach We use a Breadth-First Search (BFS) approach starting from the border 'O's. Any......
Leetcode - 200. Number of Islands
🔍 Approach: BFS We traverse each cell in the grid. When we encounter a land cell ("1")......
Leetcode - 98. Validate Binary Search Tree
🌲 Two Elegant Ways to Validate a Binary Search Tree (BST) in JavaScript A Binary Search......
Leetcode - 230. Kth Smallest Element in a BST
🧠 Approach: Inorder Traversal (Because BST is Sorted Inorder) In a BST, an inorder......
530. Minimum Absolute Difference in BST
🧠 Approach: Inorder Traversal (Sorted View of BST) In a BST, an inorder traversal gives us......
Leetcode - 103. Binary Tree Zigzag Level Order Traversal
🧠 Approach: BFS with Direction Flag This is a slight variation of Level Order Traversal......
Leetcode - 102. Binary Tree Level Order Traversal
🧠 Approach: Breadth-First Search (BFS) This is a textbook case for BFS using a queue. You......
Leetcode - 637. Average of Levels in Binary Tree
🧠 Approach: Level Order Traversal (BFS) We use Breadth-First Search (BFS) to traverse the......
Leetcode - 199. Binary Tree Right Side View
🧠 Approach: Level Order Traversal (BFS) We use Breadth-First Search (BFS) — traverse the......
Leetcode - 347. Top K Frequent Elements
🚀 Approach: Bucket Sort (Linear Time) Instead of sorting elements by frequency (which......
Leetcode - 236. Lowest Common Ancestor of a Binary Tree
🧭 Intuition Behind the Recursive Approach Here’s the deal. We’re going to: Start at the......
Leetcode - 222. Count Complete Tree Nodes
🧠 Intuition When you're at any node: Count yourself → that’s 1 Count everything in your......
Leetcode - 173. Binary Search Tree Iterator
🧠 Approach Why In-order? In-order traversal (Left → Root → Right) returns......
Leetcode - 124. Binary Tree Maximum Path Sum
When working with binary trees, it's common to process each node with post-order traversal (left →......
Leetcode - 129. Sum Root to Leaf Numbers
Approach To solve this problem, we can use a Depth-First Search (DFS) strategy to traverse......
Leetcode - 112. Path Sum
🧠 Approach: Recursive DFS To determine if a path from root to leaf equals a target sum, we......
Leetcode - 114. Flatten Binary Tree to Linked List
Hey everyone! 👋 Today, let’s dive deep into a classic tree problem — flattening a binary tree into a......
By rakeshreddy512 | April 24, 2025🧠 The Ultimate FAANG Backend Developer Roadmap – For Mid-Level Engineers (2025 Edition)
If you're a backend engineer with 2–4 years of experience and dreaming of joining FAANG or a top-tier......
Leetcode - 117. Populating Next Right Pointers in Each Node II
Approach The breadth-first search (BFS) approach is ideal for this problem. By performing......
Leetcode - 106. Construct Binary Tree from Inorder and Postorder Traversal
Reconstructing a binary tree from its inorder and postorder traversal is a classic recursive problem......
By rakeshreddy512 | April 24, 2025Mastering `height: calc()` in CSS: Dynamic Layouts Made Easy
In modern web design, flexibility is key. Whether you're building a responsive dashboard, a......
Leetcode - 105. Construct Binary Tree from Preorder and Inorder Traversal
Constructing a binary tree from preorder and inorder traversal is a classic problem that teaches......
By rakeshreddy512 | April 21, 2025💪 4 Protein-Rich Smoothies to Build Muscle & Burn Fat (Tried & Tested
Smoothies aren’t just Instagram food—they're seriously powerful when it comes to fitness......
Leetcode - 101. Symmetric Tree
Checking if a binary tree is symmetric is a classic recursive problem in data structures. In this......
By rakeshreddy512 | April 21, 2025Protein Content in Common Food Sources: A Simple Guide for Everyday Eating
Protein is essential for building muscle, repairing tissues, and maintaining a healthy metabolism.......
Leetcode - 226. Invert Binary Tree
One of the most elegant problems in tree manipulation is inverting a binary tree — essentially......
Leetcode - 100. Same Tree
The “Same Tree” problem is a classic interview question that tests your understanding of tree......
Leetcode - 104. Maximum Depth of Binary Tree
Finding the maximum depth (or height) of a binary tree is one of the most classic problems in tree......
By rakeshreddy512 | April 15, 2025The Ultimate CSS Roadmap for Frontend Developers (2025 Edition
If you're diving into UI/Frontend development or want to level up your styling skills, mastering CSS......
By rakeshreddy512 | April 15, 2025Mastering CSS Position and Display: A Visual Guide for Developers
Intro: CSS layout properties like position and display often confuse developers, especially when......
By rakeshreddy512 | April 14, 2025🔍 From Data to Decisions: Understanding Binary Search Trees in JavaScript
In the last two posts, we covered what binary trees are and how to traverse them. Now it’s time to......
By rakeshreddy512 | April 14, 2025🌳 Traversing Binary Trees Like a Pro: DFS vs. BFS Explained Visually
Now that we’ve covered the basics of binary trees in our first post, it's time to dive into......
By rakeshreddy512 | April 14, 2025🌳 Binary Trees Demystified: A Beginner’s Guide Using JavaScript
If you’ve ever scratched your head at the mention of binary trees or felt overwhelmed by tree data......
Leetcode - 146. LRU Cache
🔁 Building an LRU Cache in JavaScript (The Right Way) Imagine you're building a browser,......
Leetcode - 86. Partition List
🔍 Approach To solve this cleanly, we use the two-pointer technique: Create two dummy......
Leetcode - 61. Rotate List
🔄 Approach: Calculate the length of the list. Connect the tail to the head to make it......
By rakeshreddy512 | April 12, 202540 Profound TV Series That Will Actually Improve You
If you're like me, you want your screen time to be meaningful—not just mindless entertainment. Some......
Leetcode - 82. Remove Duplicates from Sorted List II
💡 Approach The idea is to remove all nodes that have duplicate values, even the first......
By rakeshreddy512 | April 10, 2025🎨 Mastering CSS Selectors: How to Target Only What You Want
Ever wondered why a CSS style you wrote is affecting everything — or nothing at all? That’s because......
Leetcode - 19. Remove Nth Node From End of List
You're given a singly linked list. Your task is to remove the nth node from the end and return the......
By rakeshreddy512 | April 9, 2025Custom Theming in Ant Design v5 with Dynamic Theme Switching
Ant Design v5 introduced a powerful theming system built around design tokens, making it easier than......
By rakeshreddy512 | April 8, 2025Future-Proofing Your Software Career in the Age of AI
As artificial intelligence continues to evolve, many developers are wondering: "Will AI take over my......
Leetcode - 25. Reverse Nodes in k-Group
💡 Approach The idea is to reverse each group of k nodes while maintaining the correct......
Leetcode - 206. Reverse Linked List
Reversing a linked list is a common problem in coding interviews and data structures. In this blog,......
Leetcode - 92. Reverse Linked List II
Approach Find the leftPrev Node** Create a dummy node to handle edge cases (like when......
By rakeshreddy512 | April 2, 2025Mastering React Design Patterns: HOC, Render Props, and Compound Components
Introduction React is one of the most popular frontend libraries, known for its......
By rakeshreddy512 | April 2, 2025Understanding Redux Slices: A Beginner-Friendly Guide
Redux has been the go-to state management library for React applications, but traditional Redux......
By rakeshreddy512 | April 2, 2025Micro Frontend Architecture Explained
Microfrontend architecture allows breaking a monolithic frontend into smaller, independent apps that......
By rakeshreddy512 | April 2, 2025React Context API vs Redux: Which One Should You Use?
When managing state in a React application, two common approaches are React Context API and Redux.......
By rakeshreddy512 | March 31, 2025The Ultimate Guide to Losing Fat While Gaining Muscle (Body Recomposition)
Introduction Many people believe that you can either lose fat or gain muscle—but not both......
By rakeshreddy512 | March 29, 2025How to Become Super Smart, Mentally Strong, and Boost Brain Power
How to Become Super Smart, Mentally Strong, and Boost Brain Power Introduction Many people believe......
By rakeshreddy512 | March 27, 2025Food Delivery System – Low Level Design (Cleartax Machine Coding Round)
Low-Level Design (LLD) of ClearFood in JavaScript Introduction ClearFood is a......
By rakeshreddy512 | March 27, 2025what is webpack ?
Webpack is a module bundler for JavaScript applications. It takes all your files (JavaScript, CSS,......
Leetcode - 138. Copy List with Random Pointer
Copy List with Random Pointer – JavaScript Approach Problem Statement You are......
Leetcode - 21. Merge Two Sorted Lists
# Merging Two Sorted Linked Lists: Approach, Complexity, and Code Merging two sorted linked lists is......
By rakeshreddy512 | March 21, 2025Workout and Diet based on Inbody Report
💪 Complete Exercise & Nutrition Plan for Muscle Growth & Fat Loss (Based on Your......
Leetcode - 2. Add Two Numbers
Understanding Carry in Linked List Addition Key Concepts Numbers are stored in......
Creating and Working with Linked Lists in JavaScript
Creating and Working with Linked Lists in JavaScript Introduction In......
Leetcode - 150. Evaluate Reverse Polish Notation
Evaluating Reverse Polish Notation (RPN) – Approach & Learnings ......
Leetcode - 155. Min Stack
Implementing MinStack in JavaScript Problem Statement Design a stack that......
Leetcode - 71. Simplify Path
Using Stack /** * @param {string} path * @return {string} */ var simplifyPath = function (path)......
Leetcode - 20. Valid Parentheses
Approach We loop through chars of s , if its a closing bracket we compare with last element in stack......
Leetcode - 452. Minimum Number of Arrows to Burst Balloons
Intuition The problem requires us to find the minimum number of arrows needed to burst all......
Leetcode - 57. Insert Interval
Javascript Code /** * @param {number[][]} intervals * @param {number[]} newInterval * @return......
Leetcode - 56. Merge Intervals
Using Sorting Chapter 1 /** * @param {number[][]} intervals * @return {number[][]} ......
Leetcode - 228. Summary Ranges
Two Pointer Approach Javascript Code /** * @param {number[]} nums * @return {string[]} */ var......
By rakeshreddy512 | March 18, 2025Javascript - Basics of using built-in Set method
JavaScript Set - Concise Notes 🚀 🔹 What is a Set? A Set is a built-in......
Leetcode - 128. Longest Consecutive Sequence
Javascript Code /** * @param {number[]} nums * @return {number} */ var longestConsecutive =......
Leetcode - 219. Contains Duplicate II
Javascript Code /** * @param {number[]} nums * @param {number} k * @return {boolean} */ var......
Leetcode - 202. Happy Number
Using Hashmap Store all the numbers , and check for repeated number if repetition occurs then its......
Leetcode - 1. Two Sum
Using Hashmap (Optimal solution) /** * @param {number[]} nums * @param {number} target *......
Leetcode - 49. Group Anagrams
Using Sorting /** * @param {string[]} strs * @return {string[][]} */ var groupAnagrams =......
Leetcode - 242. Valid Anagram
Approach 1 /** * @param {string} s * @param {string} t * @return {boolean} */ var isAnagram =......
Leetcode - 290. Word Pattern
Javascript Code /** * @param {string} pattern * @param {string} s * @return {boolean} */ var......
Leetcode - 205. Isomorphic Strings
Javascript Code /** * @param {string} s * @param {string} t * @return {boolean} */ var......
By rakeshreddy512 | March 17, 2025OAuth vs SAML
Let's break it down: OAuth and SAML are both protocols used for authentication and authorization, but......
By rakeshreddy512 | March 17, 2025Sockets Basics
📝 Notes on Sockets and Their Importance What is a Socket? A socket is a......
Leetcode - 383. Ransom Note
🚀 JavaScript Map (HashMap) Basics Definition: A Map stores key-value pairs and maintains......
Leetcode - 289. Game of Life
Cell State Mapping: Original State New State Transitional Value Meaning 1......
By rakeshreddy512 | March 16, 2025Big O cheat sheet
A post by Rakesh Reddy Peddamallu...
Leetcode - 73. Set Matrix Zeroes
Javascript Code /** * @param {number[][]} matrix * @return {void} Do not return anything, modify......
Leetcode - 48. Rotate Image
/** * @param {number[][]} matrix * @return {void} Do not return anything, modify matrix in-place......
System Design resources for Interview Preparation
awesome-system-design-resources system-design-primer...
By rakeshreddy512 | March 8, 2025Diet plan to reduce body fat
Goal: Reduce Body Fat (from 26% to ~15-18%) While Maintaining Muscle Since you are 75 kg......
Leetcode - 54. Spiral Matrix
Javascript Code /** * @param {number[][]} matrix * @return {number[]} */ var spiralOrder =......
By rakeshreddy512 | March 7, 2025Backend Interview strategy
Here's a structured plan to help you prepare effectively: 1. Data Structures &......
By rakeshreddy512 | March 7, 2025Backend Interview preparation plan - 6 week
Here’s a detailed 6-week backend interview preparation plan tailored for 3 years of experience: ......
Leetcode - 36. Valid Sudoku
Javascript Code /** * @param {character[][]} board * @return {boolean} */ const checkInRow =......
Leetcode - 76. Minimum Window Substring
Javascript Code /** * @param {string} s - The input string * @param {string} t - The target......
Leetcode - 30. Substring with Concatenation of All Words
Javascript Code /** * @param {string} s * @param {string[]} words * @return {number[]} */ var......
Leetcode - 3. Longest Substring Without Repeating Characters
Javascript Code /** * @param {string} s * @return {number} */ var lengthOfLongestSubstring =......
Leetcode - 209. Minimum Size Subarray Sum
/** * @param {number} target * @param {number[]} nums * @return {number} */ var minSubArrayLen =......
Leetcode - 15. 3Sum
Javascript Code /** * @param {number[]} nums * @return {number[][]} */ var threeSum = function......
Leetcode - 11. Container With Most Water
Javascript Code /** * @param {number[]} height * @return {number} */ var maxArea = function......
Leetcode - 167. Two Sum II - Input Array Is Sorted
Javascript Code /** * @param {number[]} numbers * @param {number} target * @return {number[]} ......
Leetcode - 125. Valid Palindrome
Javascript Code /** * @param {string} s * @return {boolean} */ var isPalindrome = function (s)......
Leetcode - 68. Text Justification
Javascript Code /** * @param {string[]} words * @param {number} maxWidth * @return {string[]} ......
Leetcode - 28. Find the Index of the First Occurrence in a String
Javascript Code var strStr = function (haystack, needle) { if (needle.length === 0) return 0; ......
Leetcode - 6. Zigzag Conversion
/** * @param {string} s * @param {number} numRows * @return {string} */ var convert =......
Leetcode - 14. Longest Common Prefix
Javascript Code Considering the first word as a whole as prefix ; we iterate for a mismatch and......
Leetcode - 58. Length of Last Word
/** * @param {string} s * @return {number} */ var lengthOfLastWord = function(s) { let words......
Leetcode - 12. Integer to Roman
/** * @param {number} num * @return {string} */ var intToRoman = function(num) { let......
Leetcode - 13. Roman to Integer
Explanation The trick is IV is 4 because , I which is 1 is less than V which is 5 so we check in the......
Leetcode - 42. Trapping Rain Water
Mathematical function Javascript code /** * @param {number[]} height * @return {number} */ var......
Leetcode - 135. Candy
/** * @param {number[]} ratings * @return {number} */ var candy = function(ratings) { const......
Leetcode - 134. Gas Station
/** * @param {number[]} gas * @param {number[]} cost * @return {number} */ var......
Leetcode - 380. Insert Delete GetRandom O(1)
class RandomizedSet{ constructor() { this.hashMap = new Map() this.list = []; ......
Leetcode - 274. H-Index
/** * @param {number[]} citations * @return {number} */ var hIndex = function(citations) { ......
Leetcode - 45. Jump Game II
The question says that we can be always able to reach the end , only that we need to find is the min......
Leetcode - 55. Jump Game
so this is a greedy approach our goal is to reach the last index , so we try to reach to index......
Leetcode - 121. Best Time to Buy and Sell Stock
/** * @param {number[]} prices * @return {number} */ var maxProfit = function(prices) { ......
Leetcode - 189. Rotate Array
Naive Approach In this i'm just using an extra array to store /** * @param {number[]} nums *......
Leetcode - 169. Majority Element
Is it possible to do in O(1) time complexity ? There are multiple ways to solve this problem One......
Leetcode - 80. Remove Duplicates from Sorted Array II
/** * @param {number[]} nums * @return {number} */ var removeDuplicates = function(nums) { ......
Leetcode - 26. Remove Duplicates from Sorted Array
There are multiple ways to solve this but we need to solve it in inplace as mentioned in the problem......
Salary breakdown in india
A post by Rakesh Reddy Peddamallu...
Leetcode - 392. Is Subsequence
Since we need to check every character of s to be sequentially present in t , if we find the......
Leetcode - 283. Move Zeroes
Naive Approach /** * @param {number[]} nums * @return {void} Do not return anything, modify nums......
Leetcode - 443. String Compression
Need to update the solution Please read the question completely before going through the......
Leetcode - 334. Increasing Triplet Subsequence
Tried this but not a right solution /** * @param {number[]} nums * @return {boolean} */ var......
Leetcode - 238. Product of Array Except Self
So we should not be using the division operator as the question says but adding the code......
Leetcode - 151. Reverse Words in a String
Naive Approach /** * @param {string} s * @return {string} */ var reverseWords = function(s) { ......
Leetcode - 345. Reverse Vowels of a String
Naive Approach /** * @param {string} s * @return {string} */ var reverseVowels = function(s)......
Leetcode - 605. Can Place Flowers
To solve the problem we are going to iterate through the flowerbed and check for 3 things , left ,......
Leetcode - 1431. Kids With the Greatest Number of Candies
Got the brute force solution Javascript Code /** * @param {number[]} candies * @param {number}......
Leetcode - 1071. Greatest Common Divisor of Strings
Approach -> String is considered as divisor , when the lengths of both strings str1 and str2 is......
Leetcode - 1768. Merge Strings Alternately
Heres , the solution try to understand the code 🙃 /** * @param {string} word1 * @param {string}......
By rakeshreddy512 | September 2, 2024Preparation Plan - SDE2
Follow SDE2 Guide Grokking System Design Fundamentals Grokking the System Design......
By rakeshreddy512 | August 29, 2024What is API Gateway ?
Today we will go through another fundamental component of system design , API Gateway It is an......
By rakeshreddy512 | June 24, 2024Leetcode - 207. Course Schedule
U can read the question properly and give a try once before coming to the solution Incase you have......
Leetcode - 503. Next Greater Element II
key - in order to start in circular way -> generally we iterate starting from i=0 , j = (i+1) ......
Leetcode - 929. Unique Email Addresses
Lets quickly go into the solution for the unique email addresses problem we can see every email in......
Leetcode - 133. Clone Graph
/** * // Definition for a Node. * function Node(val, neighbors) { * this.val = val ===......
Leetcode - 1. Two Sum
Solution that i got , not a good one but at-least mine 🙃 , the Time Complexity is O(n^2) which is......
Leetcode - 70. Climbing Stairs
Initial Solution /** * @param {number} n * @return {number} */ var climbStairs = function(n) { ......
Leetcode - 645. Set Mismatch
Basically we need to return duplicated item and the missing item in array . since the numbers are......
Leetcode - 725. Split Linked List in Parts
Lets get into the solution of the problem . Basically we need to split the linked list in k parts......
Leetcode - 845. Longest Mountain in Array
Firstly i couldn't solve on my own 😅 , so i went through this video U can visualize the mountains......
Leetcode - 796. Rotate String
so basically we have a string s , and if its possible to rotate it and get to the string goal then we......
