Java DSA: Longest Substring Without Repeating Characters

🚀 Day 37 / 180 – DSA with Java 🚀 📘 Topic Covered: Arrays & Two-Pointer Technique 🧩 Problem Solved: Squares of a Sorted Array Problem: Given a sorted array of integers (including negatives), return a new array of the squares of each number, also sorted in non-decreasing order. Approach: Used a two-pointer approach from both ends of the array. Compared squares of elements and filled the result array from the end to maintain sorted order efficiently. Key Learning: ✔️ Handling negative values in sorted arrays ✔️ Using two-pointer technique for optimal solutions ✔️ Avoiding extra sorting to achieve O(n) time complexity If you’re also preparing for DSA, let’s connect and learn together 🤝 #DSA #Java #180DaysOfCode #LearningInPublic #Arrays #ProblemSolving #Consistency 

🚀 Day 34 / 180 – DSA with Java 🚀 📘 Topic Covered: Arrays & Basic Construction 🧩 Problem Solved: Concatenation of Array Problem: Given an integer array nums, create a new array that contains the elements of nums twice in sequence. Approach: Created a new array with double the size of the original array and filled the first half with the original elements, then copied the same elements again into the second half. Key Learning: ✔️ Practicing array construction and indexing ✔️ Understanding how to manipulate array sizes ✔️ Writing clean logic for simple transformation problems If you’re also preparing for DSA, let’s connect and learn together 🤝 #DSA #Java #180DaysOfCode #LearningInPublic #Arrays #ProblemSolving #Consistency 

🚀 DSA Learning Journey | Day 9 | Java Solved “125. Valid Palindrome.” 💡 Key Idea: Used Two Pointers while ignoring non-alphanumeric characters and comparing characters in a case-insensitive way. ⚙ Implementation • Language: Java • Time Complexity: O(n) • Space Complexity: O(1) 📚 Learning how two-pointer technique simplifies string validation problems. #Java #DSA #LeetCode #ProblemSolving #TwoPointers #JavaDeveloper

🚀 Day 33 / 180 – DSA with Java 🚀 📘 Topic Covered: Arrays & Index Manipulation 🧩 Problem Solved: Shuffle the Array Problem: Given an array in the form [x1, x2, ..., xn, y1, y2, ..., yn], rearrange it to [x1, y1, x2, y2, ..., xn, yn]. Approach: Used two pointers to track elements from the first and second halves of the array, then alternately placed them into a new array to achieve the required shuffle pattern. Key Learning: ✔️ Managing multiple pointers in array problems ✔️ Practicing index-based rearrangement ✔️ Maintaining correct ordering while constructing a new array If you’re also preparing for DSA, let’s connect and learn together 🤝 #DSA #Java #180DaysOfCode #LearningInPublic #Arrays #ProblemSolving #Consistency

Day 65 of #100DaysOfLeetCode 💻✅ Solved “Majority Frequency Group” problem in Java. Approach: • Created a frequency array of size 26 for all characters • Counted occurrences of each character in the string • For each unique frequency, counted how many characters share that frequency • Selected the frequency with the highest group size • In case of tie, chose the higher frequency • Built the result string with characters having the selected frequency Performance: ✓ Runtime: 5 ms (Beats 57.84% submissions) ✓ Memory: 44.51 MB (Beats 72.88% submissions) Key Learning: ✓ Practiced frequency grouping techniques ✓ Learned how to handle tie-breaking conditions ✓ Strengthened logic building with nested loops and conditions Learning one problem every single day 🚀 #Java #LeetCode #DSA #Strings #Hashing #ProblemSolving #CodingJourney #100DaysOfCode

Today I implemented Array Reversal in Java using the Two-Pointer Technique! 🔄 Logic: ∙ Set left = 0 and right = arr.length - 1 ∙ Swap elements at both ends ∙ Move pointers inward until they meet ✅ Input: {1, 2, 3, 4, 5} ✅ Output: 5 4 3 2 1 💡 Why Two-Pointer? Instead of using extra space, we swap in-place — making it O(n) time and O(1) space! No extra array needed. Just two pointers doing the work. 💪 Every small concept I practice brings me one step closer to DSA mastery. Keep building. Keep learning. 🙌 #100daysofcode #dsa #java #program #array #problem #leetcode #javadeveloper #learning

🚀 DSA Learning Journey | Day 8 | Java Solved “Longest Substring Without Repeating Characters.” 💡 Key Idea: Used Sliding Window + HashSet to maintain a window of unique characters and expand/shrink it dynamically. ⚙ Implementation • Language: Java • Time Complexity: O(n) • Space Complexity: O(n) 📚 Learning how the sliding window technique helps optimize substring problems efficiently. #Java #DSA #LeetCode #ProblemSolving #SlidingWindow #JavaDeveloper

🚀 Day 40 / 180 – DSA with Java 🚀 📘 Topic Covered: Binary Exponentiation (Fast Power) 🧩 Problem Solved: Pow(x, n) Problem: Implement a function to calculate x raised to the power n, handling both positive and negative values of n. Approach: Used Binary Exponentiation to reduce time complexity. Repeatedly squared the base and halved the exponent, multiplying the result only when needed. Also handled negative powers by taking the reciprocal. Key Learning: ✔️ Optimizing from O(n) to O(log n) ✔️ Understanding divide-and-conquer in exponentiation ✔️ Handling edge cases like negative powers If you’re also preparing for DSA, let’s connect and learn together 🤝 #DSA #Java #180DaysOfCode #LearningInPublic #ProblemSolving #Consistency 

🚀 Day 38 / 180 – DSA with Java 🚀 📘 Topic Covered: Strings & Two-Pointer Technique 🧩 Problem Solved: Is Subsequence Problem: Given two strings s and t, check whether s is a subsequence of t. Approach: Used two pointers to traverse both strings. Moved the pointer in s only when characters matched, and always moved the pointer in t, ensuring order is maintained. Key Learning: ✔️ Applying two-pointer technique on strings ✔️ Understanding subsequence vs substring ✔️ Writing clean and efficient O(n) solutions If you’re also preparing for DSA, let’s connect and learn together 🤝 #DSA #Java #180DaysOfCode #LearningInPublic #Strings #ProblemSolving #Consistency

💻 Practicing Binary to Decimal Conversion using Java Today I worked on converting a binary number into its decimal equivalent using logic and iteration. 🔍 Key Learnings: Understanding how binary digits map to powers of 2 Strengthening loop and mathematical logic Improving problem-solving skills step by step Instead of just memorizing, I focused on understanding the logic deeply and practicing with different inputs. 📌 Example: Binary: 1010 → Decimal: 10 Consistency + Practice = Progress 🚀 #Java #DSA #CodingJourney #Programming #100DaysOfCode #LearnToCode #ProblemSolving #DeveloperJourney #CodingPractice #TechSkills