Revisiting Binary Search Fundamentals with LeetCode

I was asked to find an element in an array. I said binary search. The architect said it wasn't the most optimized solution. He was right. Binary search is O(log n). Fast. Clean. Textbook answer. But if you're searching the same array multiple times, build a HashMap once and every query after that is O(1). One operation. Every time. The question I should have asked before answering: "How many times will we search this array?" That one question changes the entire answer. I wrote a full breakdown of when each approach is actually correct, linear, binary, HashMap, with real production scenarios where the wrong choice brought systems down. Link in comments. What's the most humbling technical correction you've received? #Java #DataStructures #SoftwareEngineering #Algorithms #Programming #CodingInterview #BackendDevelopment #TechPakistan #FreshGrad #LearningInPublic

Everyone believes that the technical aspects of data structures and algorithms are the most challenging. Determining which algorithm to use could be the problem. Choosing the appropriate data structure could be the solution... Choosing the ideal programming language could be the answer... or perhaps recognizing edge cases and having a thorough understanding of the issue. But in all honesty, it's not any of those. After all that, the real challenge starts when you actually sit down to write code based on your idea. That instant when you have a clear solution in mind but find it challenging to turn it into something accurate, error-free, and effective. Every little error counts. Every little thing matters. Thought-simple logic becomes complicated when put into practice. #DSA #DataStructures #Algorithms #Coding #Programming #ProblemSolving #LearnToCode #CodingJourney #DeveloperLife #CodeDaily #TechLearning

🚀 DSA Series #1 — Closest Target in Circular Array Today I solved an interesting problem involving circular arrays + shortest distance logic. 🧠 Key Insight: Instead of simulating movement, we can compute distance using modulo. 👉 Forward distance: (i - start + n) % n 👉 Backward distance: (start - i + n) % n Take the minimum of both — done in O(n) time ⚡ 📌 Complexity: O(n) time | O(1) space 💡 Learning: Circular problems often look tricky, but math simplifies everything. 🔥 Building consistency with: #DSA #Java #Coding #PlacementPreparation #100DaysOfCode If you’re on the same path, let’s connect and grow 🤝

Day 68 on LeetCode Guess Number Higher or Lower 🎯✅ Today’s problem reinforced the power of Binary Search on an answer space. 🔹 Approach Used in My Solution The goal was to identify a hidden number using the provided guess() API. Key idea in the solution: • Apply binary search between 1 and n • Pick mid and call guess(mid) • Based on the response:   – 0 → correct number found   – -1 → guessed number is too high → move left   – 1 → guessed number is too low → move right • Continue narrowing the search space until the number is found This is a perfect example of searching efficiently using feedback. ⚡ Complexity: • Time Complexity: O(log n) • Space Complexity: O(1) 💡 Key Takeaways: • Strengthened understanding of binary search with external APIs • Learned how to adjust search space based on feedback • Reinforced the concept of searching on answer space 🔥 Another solid step in mastering binary search patterns! #LeetCode #DSA #Algorithms #DataStructures #BinarySearch #DivideAndConquer #ProblemSolving #Coding #Programming #Cpp #STL #SoftwareEngineering #ComputerScience #CodingPractice #DeveloperLife #TechJourney #CodingDaily #100DaysOfCode #BuildInPublic #AlgorithmPractice #CodingSkills #Developers #TechCommunity #SoftwareDeveloper #EngineeringJourney

🚀 Day 56 of my DSA Journey Today, I worked on a Hard-level problem from LeetCode: 👉 Problem #4 – Median of Two Sorted Arrays (LeetCode) This problem is well-known for its complexity and is frequently asked in top product-based companies. 💡 What I focused on: Understanding the problem deeply instead of jumping directly to the optimal solution Implementing a merge + sort approach to build a clear foundation Applying the two-pointer technique to efficiently identify the median Handling both odd and even length cases carefully ⚙️ Approach Used: Merged both input arrays into a single array Sorted the combined array Used two pointers (i and j) moving towards the center Determined the median based on whether the length is odd or even 📈 Key Learning: Even though the optimal solution has a time complexity of O(log(min(m, n))), building a correct and intuitive approach first is crucial. It strengthens problem-solving skills and helps in understanding advanced techniques later. 🎯 Takeaway: Consistency and clarity in logic are more important than immediately writing the most optimized code. 🔥 Step by step, moving closer to mastering Data Structures & Algorithms. #DSA #LeetCode #ProblemSolving #Java #CodingJourney #PlacementPreparation #Consistency #Learning

🚀  Day 29 LeetCode Problem Solved: Longest Consecutive Sequence (128) Today I solved an interesting Data Structures & Algorithms problem on LeetCode. 💻 🔹 Problem: Given an unsorted array of integers, find the length of the longest consecutive elements sequence in O(n) time complexity. 🔹 Example: Input: [100, 4, 200, 1, 3, 2] Output: 4 👉 The longest consecutive sequence is [1,2,3,4]. 🔹 Approach: Instead of sorting the array (which takes O(n log n)), I used a HashSet to achieve O(n) time complexity. ✔ Store all numbers in a HashSet ✔ Identify the start of a sequence (num - 1 not present in the set) ✔ Expand the sequence forward (num + 1, num + 2...) ✔ Track the maximum length 🔹 Complexity: ⏱ Time Complexity: O(n) 📦 Space Complexity: O(n) 💡 Key Learning: Using HashSet efficiently can help optimize problems that involve searching and sequence detection. Excited to keep learning and improving problem-solving skills! 🚀 #leetcode #coding #java #datastructures #algorithms #softwaredeveloper #programming #codingjourney

Sometimes progress is not about solving new problems, but about revisiting what we’ve learned. Day 28/100 — Data Structures & Algorithms Journey (Revision Day) Today, I focused on revising key problems and concepts from the past few days to strengthen my understanding. Topics Revised: - Dynamic Programming (Interleaving String) - Bit Manipulation (Single Number II) - Linked List (Rotate List) - String Matching (Bulls and Cows) - Greedy + Stack (Remove K Digits) - Two Pointer Technique (Two Sum II) - Concurrency (Print Zero Even Odd) What I focused on: - Understanding the intuition behind each solution - Revisiting optimized approaches - Practicing dry runs without looking at code - Strengthening problem-solving patterns Key Takeaways: Revision helps convert knowledge into long-term memory Recognizing patterns is more important than memorizing solutions Confidence grows when concepts are revisited Consistency is the real key to improvement This revision helped me connect multiple concepts and improve my problem-solving clarity. #DSA #LeetCode #Revision #ProblemSolving #SoftwareEngineering #CodingJourney #100DaysOfCode #TechLearning #DeveloperJourney #Programming #Python #InterviewPreparation #CodingSkills #ComputerScience #FutureEngineer #TechCareers #SoftwareDeveloper #LearnInPublic #OpenToWork

🚀 Day 84 – DSA Journey | Maximum Depth of Binary Tree Continuing my daily DSA practice, today I focused on understanding tree depth and recursive problem solving. 📌 Problem Practiced: Maximum Depth of Binary Tree (LeetCode 104) 🔍 Problem Idea: Find the maximum depth (or height) of a binary tree — the number of nodes along the longest path from the root to a leaf node. 💡 Key Insight: The depth of a tree depends on its subtrees. At every node, we can recursively calculate the depth of left and right subtrees and take the maximum. 📌 Approach Used: • If the node is null → depth is 0 • Recursively calculate depth of left subtree • Recursively calculate depth of right subtree • Return 1 + max(left, right) 📌 Concepts Strengthened: • Binary tree traversal • Recursion • Divide and conquer approach • Tree height calculation ⏱️ Time Complexity: O(n) 📦 Space Complexity: O(h) (recursion stack) 🔥 Today’s takeaway: Breaking problems into smaller subproblems using recursion makes complex tree problems much easier to handle. On to Day 85! 🚀 #Day84 #DSAJourney #LeetCode #BinaryTree #Recursion #Java #ProblemSolving #Coding #LearningInPublic #Consistency

🚀 Solved a neat Difference Array problem today! 💡 Problem: Given an array and a set of range queries, determine whether it’s possible to make the entire array zero using the allowed operations. 🧠 Approach: Instead of applying each query directly (which would be slow), I used: • Difference Array for efficient range updates • Prefix Sum to compute actual impact at each index ⚡ Key Idea: Each query contributes to a range. By marking where the effect starts and ends, we can efficiently calculate how many times each index can be reduced. Then, for every index: • Compare available operations with required value • If available < required → not possible 📈 Complexity: O(n + q) — efficient and scalable 🔥 Key Learning: Using a Difference Array avoids repeated work and helps optimize range-based problems significantly. #LeetCode #DSA #Java #Coding #ProblemSolving #Arrays #Algorithms

🚀 Day 26/60 — LeetCode Discipline Problem Solved: Remove Element (Revision) Difficulty: Easy Today’s practice focused on revisiting a fundamental array problem involving in-place modification. The task was to remove all occurrences of a given value without using extra space, while efficiently maintaining the remaining elements. The solution leverages a simple yet powerful approach of iterating through the array and overwriting unwanted elements. Problems like this reinforce the importance of space optimization and clean in-place operations, which are often crucial in real-world scenarios. 💡 Focus Areas: • Strengthened in-place array manipulation • Practiced efficient element filtering • Reinforced two-pointer style iteration • Improved understanding of space optimization • Focused on writing concise and readable code ⚡ Performance Highlight: Achieved 0 ms runtime (100% performance) on submission. Simple problems, when practiced with discipline, continue to sharpen the core of problem-solving ability. #LeetCode #60DaysOfCode #100DaysOfCode #DSA #Arrays #TwoPointers #Algorithms #DataStructures #ProblemSolving #CodingJourney #SoftwareEngineering #Programming #Developers #TechCareers #Java