Java DSA: Length of Last Word in String

🚀 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 

🚀 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 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 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 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 

🚀 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

🚀 DSA Learning Journey | Day 2 | Java Solved “Next Permutation.” 💡 Key Idea: Find the first decreasing element from the right, swap it with the next greater element, then reverse the remaining suffix to get the next lexicographical permutation. ⚙ Implementation • Language: Java • Time Complexity: O(n) • Space Complexity: O(1) 📚 Learning how permutation logic works and how reversing the suffix ensures the next smallest arrangement. #Java #DSA #LeetCode #ProblemSolving #JavaDeveloper #Algorithms

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

🚀 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

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