Java DSA Day 15: Valid Palindrome with Two-Pointer Technique

🚀 Day 32 / 180 – DSA with Java 🚀 📘 Topic Covered: Strings & Sliding Window Technique 🧩 Problem Solved: Longest Substring Without Repeating Characters Problem: Given a string, find the length of the longest substring without repeating characters. Approach: Used a sliding window technique with two pointers and a hash array to track the last occurrence of characters. Whenever a repeating character appeared within the current window, adjusted the left pointer to maintain a substring with unique characters. Key Learning: ✔️ Applying sliding window for substring problems ✔️ Using hashing for constant-time character tracking ✔️ Optimizing from brute-force to O(n) time complexity If you’re also preparing for DSA, let’s connect and learn together 🤝 #DSA #Java #180DaysOfCode #LearningInPublic #Strings #ProblemSolving #Consistency

🚀 Day 28 / 180 – DSA with Java 🚀 📘 Topic Covered: Strings & Sliding Window 🧩 Problem Solved: Divisor Substrings Problem: Given an integer num and an integer k, find the number of substrings of length k from the digits of num such that the substring value divides num. Approach: Converted the number to a string and used a sliding window of size k to extract substrings. Each substring was converted back to an integer and checked whether it divides the original number. Key Learning: ✔️ Applying sliding window technique on strings ✔️ Converting between numeric and string representations ✔️ Handling edge cases like division by zero If you’re also preparing for DSA, let’s connect and learn together 🤝 #DSA #Java #180DaysOfCode #LearningInPublic #Strings #ProblemSolving #Consistency

🚀 Day 27 / 180 – DSA with Java 🚀 📘 Topic Covered: Strings & Reverse Traversal 🧩 Problem Solved: Length of Last Word Problem: Given a string containing words separated by spaces, find the length of the last word. Approach: Started traversing the string from the end, skipped trailing spaces first, and then counted characters until encountering another space or reaching the beginning of the string. Key Learning: ✔️ Efficient reverse traversal in strings ✔️ Handling edge cases like trailing spaces ✔️ Writing simple yet optimized string logic If you’re also preparing for DSA, let’s connect and learn together 🤝 #DSA #Java #180DaysOfCode #LearningInPublic #Strings #ProblemSolving #Consistency

🚀 Day 21 / 180 – DSA with Java 🚀 📘 Topic Covered: Strings & Pattern Detection 🧩 Problem Solved: Largest 3-Digit Repeating Number in a String Problem: Given a numeric string, find the largest substring of length 3 where all three digits are the same. If no such substring exists, return an empty string. Approach: Traversed the string and checked every group of three consecutive characters. Whenever three identical digits were found, compared them lexicographically to track the largest valid substring. Key Learning: ✔️ Detecting fixed-length patterns in strings ✔️ Using lexicographical comparison effectively ✔️ Careful boundary handling during traversal If you’re also preparing for DSA, let’s connect and learn together 🤝 #DSA #Java #180DaysOfCode #LearningInPublic #Strings #ProblemSolving #Consistency 

👌 🚀 Day 17 / 180 – DSA with Java 🚀 📘 Topic Covered: Arrays & Reversal Algorithm 🧩 Problem Solved: Rotate Array Problem: Rotate an array to the right by k steps, modifying it in-place without using extra space. Approach: Used the reversal algorithm: 1️⃣ Reversed the entire array 2️⃣ Reversed the first k elements 3️⃣ Reversed the remaining elements This efficiently achieved rotation in O(n) time with O(1) extra space. Key Learning: ✔️ Using reversal technique for array manipulation ✔️ Breaking complex operations into smaller steps ✔️ Writing optimized in-place solutions If you’re also preparing for DSA, let’s connect and learn together 🤝 #DSA #Java #180DaysOfCode #LearningInPublic #Arrays #ProblemSolving #Consistency 

🚀 Day 30 / 180 – DSA with Java 🚀 📘 Topic Covered: Strings & Sorting Technique 🧩 Problem Solved: Longest Common Prefix Problem: Given an array of strings, find the longest common prefix shared among all the strings. Approach: Sorted the array of strings and compared only the first and last strings. Since sorting groups similar prefixes together, the common prefix between these two strings represents the common prefix for the entire array. Key Learning: ✔️ Using sorting to simplify string comparison problems ✔️ Observing patterns to reduce unnecessary checks ✔️ Efficient prefix detection in string arrays If you’re also preparing for DSA, let’s connect and learn together 🤝 #DSA #Java #180DaysOfCode #LearningInPublic #Strings #ProblemSolving #Consistency 

🚀 Day 31 / 180 – DSA with Java 🚀 📘 Topic Covered: Strings & Substring Search 🧩 Problem Solved: Find the Index of the First Occurrence in a String Problem: Given two strings haystack and needle, return the index of the first occurrence of needle in haystack. If it is not present, return -1. Approach: Traversed the main string and checked potential starting positions where the first character matched. Then compared the substring of the same length as the target string to verify a complete match. Key Learning: ✔️ Understanding substring search logic ✔️ Optimizing comparisons by checking the first character first ✔️ Practicing careful boundary handling in string traversal If you’re also preparing for DSA, let’s connect and learn together 🤝 #DSA #Java #180DaysOfCode #LearningInPublic #Strings #ProblemSolving #Consistency 

🚀 DSA in Java – Day 76 ✅ Today I solved the “Check if Binary String Has at Most One Segment of Ones” problem on LeetCode. 💡 Problem Idea: Given a binary string, we need to check whether there is at most one continuous segment of '1's in the string. 🧠 Approach: Traverse the string using a loop. Count how many segments of '1' appear. If the count becomes greater than 1, return false. Otherwise return true. ⚡ Key Concepts Practiced: String traversal While loop Character comparison Logical conditions Consistency in solving problems every day is helping me strengthen my problem-solving and logical thinking skills in Java. #DSA #Java #LeetCode #ProblemSolving #CodingJourney #WomenInTech #100DaysOfCode

🚀 Day 19 / 180 – DSA with Java 🚀 📘 Topic Covered: Strings & Greedy Traversal 🧩 Problem Solved: Largest Odd Number in a String Problem: Given a numeric string, return the largest-valued odd-numbered substring. If no odd digit exists, return an empty string. Approach: Traversed the string from right to left to find the first odd digit. Once found, returned the substring from the start up to that index to ensure the largest possible odd number. Key Learning: ✔️ Observing patterns to reduce unnecessary computation ✔️ Efficient right-to-left traversal ✔️ Applying greedy thinking in string problems If you’re also preparing for DSA, let’s connect and learn together 🤝 #DSA #Java #180DaysOfCode #LearningInPublic #Strings #ProblemSolving #Consistency

Day 49 of #100DaysOfLeetCode 💻✅ Solved #387. First Unique Character in a String problem in Java. Approach: • Created an array of size 26 to store the frequency of each character • Traversed the string and counted how many times each character appears • Traversed the string again to find first character with frequency equal to 1 • Returned the index of that character • If no unique character is found, returned -1 Performance: ✓ Runtime: 6 ms (Beats 84.58% submissions) ✓ Memory: 47.16 MB (Beats 36.29% submissions) Key Learning: ✓ Practiced using frequency arrays for string problems ✓ Learned how counting characters helps find unique elements efficiently ✓ Strengthened understanding of string traversal and indexing Learning one problem every single day 🚀 #Java #LeetCode #DSA #Strings #ProblemSolving #CodingJourney #100DaysOfCode