LeetCode Challenge Day 8: Binary String Uniqueness with Cantor Diagonalization

🧠 Day 37/75: Root-to-Leaf Logic In coding, as in life, we often have to explore different paths to see which one leads to our target. Today’s problem, "Path Sum," is a classic exercise in exactly that. Using Recursion, I built a solution that explores every branch of a Binary Tree until it finds a path that hits the exact target sum. It’s a great reminder that even when a structure looks complex, a consistent, step-by-step approach will eventually find the right way through. The Stats: 📅 37 Days of consecutive coding. ⚡ 100% Beats Runtime (0ms) — Performance is key! 🎯 Focus: Tree Traversals & Base Case Logic. The second month of this challenge is providing some of the most interesting logic puzzles yet. Staying focused and keeping the streak alive! 💻🔥 #Consistency #100DaysOfCode #Algorithms #JavaDeveloper #TechGrowth #ProblemSolving #LeetCodeChallenge #TreeTraversal

🔍 Problem Solved: Perfect Number (LeetCode #507) Worked on the “Perfect Number” problem, which focuses on divisor concepts and efficient computation. 📌 Problem Summary: A number n is said to be perfect if the sum of all its positive divisors (excluding itself) equals n. 💡 Key Learning: Instead of checking all numbers up to n, we can optimize by iterating only up to √n and adding divisor pairs. 🧠 Why this problem matters: Strengthens understanding of factors and divisors Introduces optimization techniques Improves mathematical problem-solving skills 📈 Problems like this help build a strong foundation for coding interviews and competitive programming. #LeetCode #Algorithms #DataStructures #Coding #ProblemSolving #InterviewPreparation #Math #SoftwareEngineering #SavecodeS

Day 41: 90-Day Coding Challenge 🚀 Today was about mastering binary search beyond arrays and applying it to answer spaces and structured data. Focused on recognizing when the problem isn’t asking to search data directly, but to efficiently converge on the correct answer using constraints and patterns. Today’s learning highlights: ✅ Using binary search on the answer space for optimization problems with constraints ✅ Leveraging sorted matrix properties for efficient traversal instead of flattening ✅ Applying mathematical pattern building (DP/pointers) for sequence generation A key takeaway was understanding that the same technique can look very different depending on the problem’s structure. Shift perspective. Trust patterns. Refine approach. Day 41 done. On to Day 42. 💻🔥 Anchal Sharma Ikshit .. #90DayCodingChallenge #CodingJourney #ProblemSolving #BinarySearch #Matrices #DynamicProgramming #LearningJourney #Consistency #Growth

Day 66 on LeetCode — Binary Search 🔍✅ Today’s problem focused on one of the most fundamental and powerful techniques in DSA — Binary Search. 🔹 Approach Used in My Solution The goal was to find the index of a target element in a sorted array. Key idea in the solution: • Maintain two pointers: low and high • Calculate mid = low + (high - low) / 2 to avoid overflow • Compare nums[mid] with target:   – If equal → return index   – If greater → search left half   – If smaller → search right half • Continue until the search space is exhausted This approach efficiently reduces the search space by half in every step. ⚡ Complexity: • Time Complexity: O(log n) • Space Complexity: O(1) 💡 Key Takeaways: • Mastered the core concept of divide and conquer • Learned how to safely calculate mid to avoid overflow • Reinforced understanding of searching in sorted arrays efficiently 🔥 Binary Search is a must-know pattern for interviews and advanced problems! #LeetCode #DSA #Algorithms #DataStructures #BinarySearch #Arrays #DivideAndConquer #ProblemSolving #Coding #Programming #Cpp #STL #SoftwareEngineering #ComputerScience #CodingPractice #DeveloperLife #TechJourney #CodingDaily #100DaysOfCode #BuildInPublic #AlgorithmPractice #CodingSkills #Developers #TechCommunity #SoftwareDeveloper #EngineeringJourney

🔍 Concept Practiced: Abundant Number Explored the concept of “Abundant Numbers”, which are numbers where the sum of proper divisors exceeds the number itself. 📌 Key Insight: Efficient divisor calculation using √n optimization significantly reduces time complexity. 🧠 Why this matters: Strengthens understanding of number theory Improves optimization thinking Builds foundation for advanced math-based problems 📈 Even though this is not a direct LeetCode problem, it is a common concept used in coding interviews and competitive programming. #Algorithms #DataStructures #ProblemSolving #Coding #Math #InterviewPreparation #SoftwareEngineering #SavecodeS

🔥 From logic to trees — solved LeetCode #95 (Medium) 💻 Built all unique Binary Search Trees using recursion + memoization. 🔍 Key concepts: 1. Divide & Conquer 2. Recursive tree construction 3. Dynamic Programming ⚙️ Result: ✔️ Accepted ✔️ Optimized approach ✔️ Deeper understanding of problem structuring 💡 Takeaway: Strong solutions come from breaking problems into smaller, reusable pieces. #LeetCode #Algorithms #DataStructures #ProblemSolving #CodingJourney

🚀 Solved: Split Array Largest Sum (LeetCode 410) Today I worked on an interesting problem that combines Binary Search + Greedy approach. 💡 Problem Summary: Given an array and a number k, split the array into k subarrays such that the maximum sum among them is minimized. 🧠 Key Learning: Instead of brute force, we can: Apply Binary Search on the answer space Use a Greedy check function to validate splits 🔍 Core Idea: Lower bound = max element Upper bound = sum of array Minimize the largest subarray sum 📈 Time Complexity: O(n log(sum)) ✨ Problems like this really strengthen problem-solving skills around: Search space optimization Greedy decisions #LeetCode #DSA #BinarySearch #Coding #ProblemSolving #SoftwareEngineering

Computation is easy—the real challenge is knowing what to compute. In competitive programming, problems like counting pairs whose sum is divisible by k look straightforward, a vast pattern of questions of CodeForces and LeetCode revolve around this—but under contest pressure, they expose gaps in thinking efficiency. Brute force works… until it doesn’t. The real shift happens when you stop iterating over pairs and start reasoning in modular space since it reduces space from large n to defined m. Want to know, how I got this idea, try solving this problem - https://lnkd.in/gUrbzTV6 What most people miss is this: • It’s not about “optimizing loops” • It’s about changing the representation of the problem This is where many plateau—solving problems, but not upgrading their thinking model. Interestingly, this maps directly to real systems: • Hashing, partitioning, load balancing → all rely on similar modular reasoning • Efficiency comes from pre-computation and smart grouping, not brute force If you’re stuck in CP, it’s rarely a coding issue—it’s a thinking abstraction gap. How often do you step back and rethink the structure of a problem instead of optimizing your current approach? Let us discuss this further in the comments. Follow Vishu Kalier for more such deep dives. #CompetitiveProgramming #DSA #ProblemSolving #Algorithms #Coding #SystemDesign #cfbr #learninginpublic #roadtograndmaster #eternal #zomato

🚀 Day 11 of 100 Days LeetCode Challenge Problem: Complement of Base 10 Integer Today’s problem is a clean example of bit manipulation fundamentals 🔥 💡 Key Insight: To find the complement: Convert the number to binary Flip all bits (0 → 1, 1 → 0) Convert it back to decimal 👉 But here’s the trick: We only flip significant bits (ignore leading zeros) 🔍 Optimized Approach: Create a bitmask with all bits set to 1 (same length as n) Then: complement = n XOR mask 👉 Example: n = 5 → (101) mask = 111 Result = 101 ⊕ 111 = 010 → 2 🔥 What I Learned Today: XOR is powerful for bit flipping operations Bitmasking simplifies binary problems Always consider binary representation constraints 📈 Challenge Progress: Day 11/100 ✅ Bit by bit improving! LeetCode, Bit Manipulation, XOR, Binary Representation, Bitmasking, DSA Practice, Coding Challenge, Problem Solving, Algorithms #100DaysOfCode #LeetCode #DSA #CodingChallenge #BitManipulation #Binary #XOR #ProblemSolving #TechJourney #ProgrammerLife #SoftwareDeveloper #CodingLife #LearnToCode #Developers #Consistency #GrowthMindset #InterviewPrep

🚀 Staying consistent and improving problem-solving skills with each step. LeetCode Progress 15/50 — Missing Number I worked on a problem focused on arrays and mathematical optimization 🧩 💡 The challenge was to find the missing number in a given range from 0 to n using an efficient approach. 🧠 Approach: Applied the sum formula of the first n natural numbers and compared it with the actual sum of the array to identify the missing value. This avoids the need for extra space and keeps the solution efficient. ⏱ Time Complexity: O(n) 💡 What I learned: This problem highlighted how mathematical concepts can simplify problems and lead to clean and optimized solutions. 📈 Strengthening fundamentals and exploring different ways to approach the same problem efficiently. #LeetCode #DSA #ProblemSolving #Cpp #CodingJourney 🚀