Solved LeetCode problems to improve Java and DSA skills

🚀 Day 27 of 100 Days of LeetCode 📘 Problem: Generate Parentheses 💻 Language: Java ✅ Status: Accepted — Runtime: ⚡ 0 ms (Beats 100%) Today’s challenge focused on backtracking, one of the most elegant and powerful problem-solving techniques in DSA. The task was to generate all possible valid combinations of parentheses — a perfect test of recursion and logical constraints 🧩 ✨ Key Learnings: Backtracking is about exploring all possibilities, then undoing choices when needed 🔄 Understanding base cases clearly makes recursion much easier Clean recursive structures lead to elegant and efficient solutions This problem reinforced one important principle — 🧠 “Sometimes, going back is the only way to move forward — both in code and in life.” #Day27 #100DaysOfCode #LeetCode #Java #Backtracking #Recursion #ProblemSolving #CodingJourney #DSA #SoftwareDevelopment #KeepLearning #CodeEveryday

🚀 #Day19 of My Coding Journey: Mastering String Handling in Java! 📢 Strings are the backbone of data in programming, and today I dove deep into String Handling in Java. It's been incredibly valuable to understand the mechanics of manipulating data, from simple text to complex messages. 📝 Here's what I learned and practiced: 🥇Comparison Methods: Explored equals(), equalsIgnoreCase(), and compareTo() to compare strings directly and by ignoring case. 🥈Case Conversion: Used toUpperCase() and toLowerCase() to standardize text formats. ♟️Length & Character Operations: Got hands-on with length() to find the size and charAt() to access specific characters. ⏳Search Operations: Practiced using indexOf() and lastIndexOf() to pinpoint the location of characters or words. 🧩Start & End Check: Learned to use startsWith() and endsWith() for specific text verification. 🎯Modification & Cleanup: Utilized replace(), trim(), split(), and concat() for cleaning, modifying, and combining strings. 📌A key takeaway was truly understanding why strings in Java are immutable—once created, their value can't be changed. This solidifies my understanding of how Java manages memory and data integrity. 🪄This is a crucial step toward building strong fundamentals and processing real-world text data efficiently! A special thanks to my mentor Anand Kumar Buddarapu and Codegnan for their continuous guidance! Saketh Kallepu &Uppugundla Sairam #Java #StringHandling #Programming #CodingJourney #Day19 #TechSkills

🚀 Day 108 of Learning Java – Polymorphism Made Easy! Today I learned one of the most important OOP concepts in Java — Polymorphism 🔥 🔹 Poly = Many 🔹 Morphism = Forms/Behaviors ➡️ So one thing behaving in many different ways. ✅ What Polymorphism Means (Simple Language) Polymorphism lets the same method or object perform different actions depending on the situation. 📌 Example: A single function name like drive() can work differently for: Car Bike Bus Even though the method name is the same, the output changes based on the object. This makes our code clean, flexible, and easy to maintain. 🧠 Types of Polymorphism in Java 1️⃣ Compile-time Polymorphism (Method Overloading) Same method name, different parameters. 2️⃣ Run-time Polymorphism (Method Overriding) Child class gives its own version of the parent class method. 💡 Why It’s Important? ✔️ Reduces code duplication ✔️ Makes your code dynamic ✔️ Helps in writing reusable and extensible programs Excited to learn more concepts and keep leveling up every day! 🔥 #Day108 #Java #LearningJourney #OOP #Polymorphism #CodingJourney

If you’re learning #Java, you’ve probably seen the keywords #static and wondered — what’s the difference between static and non-static methods? 🤔 Let’s break it down 👇 🧩 Static Methods - Belong to the #class, not to any specific object. - Can be called without creating an #object. - Commonly used for utility or helper functions. ⚙️ Non-Static Methods -Belong to objects created from the class. -Need an instance to be called. -Can access both static and non-static members of the class. 🔑 Key takeaway: -Use 'static' when behavior doesn’t depend on 'object' data. Use 'non-static' when the method works with 'instance' variables. 💬 What’s one thing about static that confused you when you first started learning Java? Let’s discuss in the comments 👇 #Java #LearnJava #CodingForBeginners #SoftwareDevelopment #ProgrammingTips #JavaDeveloper #CodeNewbie #TechEducation

🚀 Day 29 of 100 Days of LeetCode 📘 Problem: Combination Sum 💻 Language: Java ✅ Status: Accepted — Runtime ⚡ 2 ms (Beats 86%) Today’s problem was all about backtracking — exploring all possible combinations to reach a target sum. It’s a perfect blend of recursion, decision-making, and pruning unnecessary paths 🧠 ✨ Key Learnings: Backtracking is like exploring a maze — try, backtrack, and try again until you find the exit 🌀 Each recursive call represents a “choice point” — include or skip the element Clean recursion with controlled base cases leads to clarity and precision This problem reminded me how persistence works in both code and life: 💬 “Sometimes, the path to the solution is not straightforward — you just need to keep exploring.” #Day29 #100DaysOfCode #LeetCode #Java #Backtracking #Recursion #DSA #ProblemSolving #CodingJourney #SoftwareDevelopment #KeepLearning #CodeEveryday

👋 Hi Connections! 💻 Today I worked on an interesting Java problem — finding unique pairs in an array whose sum equals a target value! 🎯 🧩 Problem: Given an array and a target, find how many unique pairs exist such that their sum = target. ⚙️ My Approach: I used the two-pointer technique on a sorted array: ➡️ Initialize two pointers (start and end). ➡️ If the current sum is less than the target → move start forward. ➡️ If the sum is greater → move end backward. ➡️ If the sum equals the target → record it, skip duplicates, and move both pointers. ✨ This avoids unnecessary comparisons and handles duplicates smartly, giving a clean O(n) solution! 💡 What I Learned: ✅ The two-pointer method is perfect for pair-sum problems. ✅ Skipping duplicates carefully improves accuracy and avoids redundancy. ✅ Thinking in patterns rather than brute-force leads to elegant solutions. Every problem solved is one more step in improving my DSA intuition and optimization mindset 💪🔥 #Java #DSA #Coding #ProblemSolving #TwoPointers #LeetCode #Programming #LearningEveryday

Hello Connection ❗ learning codding string frequency #day17 Today I practiced a core Java concept: calculating character frequency using HashMap. This small program helped me revise: 🔹 Iterating through a string using toCharArray() 🔹 Using HashMap to store counts 🔹 Applying getOrDefault() for cleaner code 🔹 Looping through entrySet() to print results 💡 Key Takeaway: Even simple problems can help us strengthen fundamentals. Mastering basics like HashMap, loops, and string manipulation makes advanced topics easier. If you're preparing for coding interviews, this is a must-practice pattern! 🔥 If you want, I can also create: ✔ A more professional version ✔ A beginner-friendly explainer ✔ A short motivational caption ✔ A carousel-style content script ✔ A Linkedin-optimized hashtag set #Java #JavaProgramming #JavaDeveloper #Coding #Programming #CodeNewbie #TechLearning #SoftwareDevelopment #HashMap #DataStructures #ProblemSolving #LearningEveryday #LearnToCode #CodeJourney #DeveloperLife #TechStudent #CodingPractice #InterviewPreparation #CodingSkills #LogicBuilding #ProgrammingBasics #DSA #TechCommunity #SoftwareEngineer #ComputerScience #TechSkills

🚀 Day 79 of My #100DaysOfCoding Challenge Problem: Find the Duplicate Number 🔹 Platform: LeetCode (#287) 🔹 Difficulty: Medium 🔹 Language: Java 💡 Problem Statement: Given an array of n + 1 integers where each integer is between 1 and n (inclusive), find the single duplicate number. You must solve the problem without modifying the array and using constant extra space. 🧠 Approach: I explored two methods for this problem: 1️⃣ Sorting Approach (Simple but not optimal): Sort the array and check for consecutive duplicate elements. Time complexity: O(n log n) 2️⃣ Floyd’s Cycle Detection Algorithm (Optimal): Think of the array as a linked list where each number points to the next index. The duplicate number causes a cycle. Using slow and fast pointers, we detect the meeting point and then find the cycle’s start — that’s our duplicate! 🧩 Java Code (Optimal Solution): class Solution { public int findDuplicate(int[] nums) { int slow = nums[0]; int fast = nums[0]; // Detect cycle do { slow = nums[slow]; fast = nums[nums[fast]]; } while (slow != fast); // Find entrance to the cycle fast = nums[0]; while (slow != fast) { slow = nums[slow]; fast = nums[fast]; } return slow; } } 🔍 Key Takeaways: Great example of applying cycle detection in array problems. Strengthened understanding of two-pointer techniques. Learned how mathematical logic can make problems space-efficient! #100DaysOfCoding #Day79 #LeetCode #Java #DSA #ProblemSolving #CodingJourney #LearningEveryday #FloydsAlgorithm

I recently held a peer-to-peer learning session with two of my friends (Slindile Nkabinde and Nokwanda Gumede) where we explored how inheritance and polymorphism truly work in Java — by looking closely at the Object class. We saw how every class in Java inherits from Object and how its methods like toString(), equals(), and hashCode() behave by default — and what really happens when we override them. It was inheritance, polymorphism, upcasting, and downcasting in action. The best part? We were learning with each other which is WeThinkCode's modus operandi. We were explaining to each other, laughing over funny practical examples that we all came up with, and really seeing how deep these concepts go. Teaching them helped me understand it all at a much deeper level. Sometimes, the best way to learn is to learn together. 💡 #Java #ObjectOrientedProgramming #SoftwareEngineering #WeThinkCode #PeerToPeerLearning #Developers