Java DSA Progress Update: 125/310 Problems Solved

Day 37 of My Java DSA Journey✨ Today I focused on improving my logic building skills and practiced problems using: 💡 Nested If-Else Conditions • Solved problems that required multiple condition checks • Learned how to structure logic clearly without confusion 🔄 Array Rotation • Understood how elements shift positions in an array • Practiced rotating arrays and tracking index changes 🔍 What I learned today: • Breaking complex conditions into smaller steps • Writing clean and readable logic • Importance of index handling in arrays ⚡ These problems may look simple, but they are essential for building strong problem-solving skills. 🎯 Takeaway: Strong logic + array basics = foundation for advanced DSA #Day36 #90DaysOfCoding #Java #DSA #Arrays #ProblemSolving #CodingJourney #Consistency

🚀 Day 36 / 180 – DSA with Java 🚀 📘 Topic Covered: Binary Search (Peak Finding) 🧩 Problem Solved: Find Peak Element Problem: Given an array, find a peak element (an element greater than its neighbors) and return its index. Approach: Used Binary Search by comparing the middle element with its neighbors. Based on the increasing or decreasing slope, moved towards the side where a peak must exist, reducing the search space efficiently. Key Learning: ✔️ Applying binary search on unsorted arrays using patterns ✔️ Understanding how slope direction guides decisions ✔️ Solving peak problems in O(log n) time If you’re also preparing for DSA, let’s connect and learn together 🤝 #DSA #Java #180DaysOfCode #LearningInPublic #BinarySearch #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

Day 70 of #100DaysOfLeetCode 💻✅ Solved #3136. Valid Word problem in Java. Approach: • Checked if the word length is at least 3 • Traversed each character in the string • Ensured all characters are either letters or digits • Checked for presence of at least one vowel • Checked for presence of at least one consonant • Returned true only if all conditions are satisfied Performance: ✓ Runtime: 1 ms (Beats 99.62% submissions) 🚀 ✓ Memory: 43.08 MB (Beats 93.16% submissions) Key Learning: ✓ Practiced string validation with multiple conditions ✓ Learned efficient use of built-in character functions ✓ Strengthened logic building for edge case handling Learning one problem every single day 🚀 #Java #LeetCode #DSA #Strings #ProblemSolving #CodingJourney #100DaysOfCode

🚀 Day 46 / 180 – DSA with Java 🚀 📘 Topic Covered: Matrix Manipulation 🧩 Problem Solved: Rotate Image Problem: Given an n x n matrix representing an image, rotate it 90 degrees clockwise in-place. Approach: First transposed the matrix by swapping rows and columns across the diagonal. Then reversed each row to complete the 90-degree clockwise rotation efficiently without extra space. Key Learning: ✔️ Breaking matrix problems into smaller transformations ✔️ Understanding transpose operations ✔️ Solving in-place matrix rotation with O(1) extra space If you’re also preparing for DSA, let’s connect and learn together 🤝 #DSA #Java #180DaysOfCode #LearningInPublic #Matrix #ProblemSolving #Consistency 💙

🚀 Day 57 of My Java DSA Journey Today I worked on a classic Dynamic Programming problem: 💡 Subset Sum Problem 🧠 Approach: • Used recursion with memoization • At each step, decided whether to include or exclude an element • Stored intermediate results to optimize performance 🔍 Key Insight: A subset with sum k exists if: We can form k without current element OR We can form k - arr[i] including current element ⚡ What I learned: • DP pattern similar to Knapsack • Importance of proper memoization • Handling boolean DP states 🔥 Complexity: • Time: O(n × k) • Space: O(n × k) 🎯 Takeaway: Many DP problems are variations of a few core patterns. #Day57 #90DaysOfCoding #DSA #DynamicProgramming #Java

🚀 Day 41 / 180 – DSA with Java 🚀 📘 Topic Covered: Matrices & Marking Technique 🧩 Problem Solved: Set Matrix Zeroes Problem: Given a matrix, if an element is 0, set its entire row and column to 0. Approach: Used two auxiliary arrays to mark rows and columns that contain zeroes. In a second pass, updated the matrix by setting elements to zero based on the marked rows and columns. Key Learning: ✔️ Handling matrix-based transformations ✔️ Using extra space for clarity and simplicity ✔️ Breaking the problem into marking and updating phases If you’re also preparing for DSA, let’s connect and learn together 🤝 #DSA #Java #180DaysOfCode #LearningInPublic #Arrays #ProblemSolving #Consistency

🚀 Day 43 / 180 – DSA with Java 🚀 📘 Topic Covered: Linked List Traversal 🧩 Problem Solved: Middle of the Linked List Problem: Given the head of a singly linked list, return the middle node. If there are two middle nodes, return the second middle node. Approach: Traversed the linked list once to count the total number of nodes. Then moved again up to the middle position and returned that node. Key Learning: ✔️ Practicing linked list traversal logic ✔️ Handling even-length edge cases correctly ✔️ Exploring multi-pass solutions before optimizing further If you’re also preparing for DSA, let’s connect and learn together 🤝 #DSA #Java #180DaysOfCode #LearningInPublic #LinkedList #ProblemSolving #Consistency

Solved LeetCode 17 – Letter Combinations of a Phone Number using backtracking in Java. Approach: Mapped each digit (2–9) to its corresponding characters using a simple array for O(1) access. Then used backtracking to build combinations digit by digit. For every digit: Pick each possible character Append → explore next digit → backtrack Key idea: Treat it like a tree of choices, where each level represents a digit and branches represent possible letters. Key learnings: Backtracking = build → explore → undo StringBuilder helps avoid unnecessary string creation Problems like this are about systematic exploration of choices Time Complexity: O(4^n * n) Space Complexity: O(n) recursion stack + output Consistent DSA practice is strengthening pattern recognition day by day. #Java #DSA #Backtracking #LeetCode #CodingInterview #SoftwareEngineering

Day 44-What I Learned In a Day(JAVA) Today I revised pattern programming in Java to strengthen my core logic and understanding of loops. What I practiced: • Star patterns • Number patterns • Pyramid patterns • Inverted patterns • Nested loop logic Pattern programming helped me improve: • Loop control (for/while) • Logical thinking • Understanding of rows & columns Every pattern I solve makes my logic stronger step by step. Consistency is the key #Java #CodingJourney #PatternProgramming #Learning #StudentDeveloper