Java Solution for LeetCode #541: Reverse String II

Day 73 of #100DaysOfLeetCode 💻✅ Solved #389. Find the Difference problem in Java. Approach: • Initialized a variable to store the sum • Added ASCII values of all characters in string t • Subtracted ASCII values of all characters in string s • The remaining value represents the extra character • Converted the result back to character and returned it Performance: ✓ Runtime: 1 ms (Beats 99.89% submissions) 🚀 ✓ Memory: 42.77 MB (Beats 97.03% submissions) Key Learning: ✓ Practiced optimized string traversal using enhanced for-loop ✓ Reinforced understanding of ASCII-based solutions ✓ Learned how mathematical approaches can simplify problems Learning one problem every single day 🚀 #Java #LeetCode #DSA #Strings #Math #ProblemSolving #CodingJourney #100DaysOfCode

Day 21 of #100DaysOfCode Today, I worked on the classic string problem: implementing the strStr() function in Java. The goal: Find the first occurrence of a substring (needle) inside another string (haystack). Approach I used: - Applied a sliding window technique - Compared substrings using "substring(i, j)" - Returned the starting index when a match is found Key learning: Understanding how index-based string operations work and how "substring()" helps in breaking down problems step-by-step. Also realized the importance of optimizing solutions to avoid unnecessary string creation. Consistency is slowly turning concepts into confidence! Looking forward to improving this further with more optimized approaches #Java #Coding #DSA #LeetCode #ProblemSolving #LearningJourney #Consistency

Day 68 of #100DaysOfLeetCode 💻✅ Solved #977. Squares of a Sorted Array problem in Java. Approach: • Traversed the array and squared each element • Used Arrays.sort() to sort the squared values • Returned the sorted array as the result Performance: ✓ Runtime: 10 ms (Beats 37.38% submissions) ✓ Memory: 47.98 MB (Beats 18.78% submissions) Key Learning: ✓ Practiced array transformation and sorting ✓ Learned how squaring affects order in sorted arrays ✓ Understood the importance of optimizing from O(n log n) to O(n) using two pointers Learning one problem every single day 🚀 #Java #LeetCode #DSA #Arrays #Sorting #ProblemSolving #CodingJourney #100DaysOfCode

Day 93 - LeetCode Journey Solved LeetCode 9: Palindrome Number in Java ✅ At first glance, it feels like a string problem… but the real challenge is solving it without converting to string. Instead of reversing the whole number, I reversed only half of it and compared both parts. This avoids overflow and keeps it efficient. Smart approach > brute force 💡 Key takeaways: • Handling edge cases (negative numbers, trailing zeroes) • Reversing only half of the number • Avoiding extra space (no string conversion) • Writing optimized mathematical logic ✅ All test cases passed ⚡ O(log n) time and O(1) space Sometimes the best solutions are the simplest ones, just a different way of thinking 🔥 #LeetCode #DSA #Java #Math #ProblemSolving #CodingJourney #InterviewPrep #Consistency #100DaysOfCode

Day 63 of #100DaysOfLeetCode 💻✅ Solved #2085. Count Common Words With One Occurrence problem in Java. Approach: • Iterated through each word in the first array • Avoided duplicate checks by ensuring each word is processed only once • Counted occurrences of the current word in both arrays • If the word appears exactly once in both arrays, incremented the result • Returned the final count Performance: ✓ Runtime: 88 ms (Beats 7.45% submissions) ✓ Memory: 46.06 MB (Beats 93.07% submissions) Key Learning: ✓ Practiced handling duplicates and frequency counting ✓ Improved understanding of string comparison in arrays ✓ Learned importance of optimizing nested loop solutions Learning one problem every single day 🚀 #Java #LeetCode #DSA #Strings #Arrays #ProblemSolving #CodingJourney #100DaysOfCode

Leetcode Question Number 1848: Minimum Distance to the Target Element. I solved an interesting problem on finding the minimum distance in an array using Java!(Leetcode Daily Challenge) Given an array, a target value, and a starting index, the task is to find the minimum distance between the start index and any occurrence of the target element. Approach I used: 1.Traverse the array 2.Check for target element 3.Calculate distance using Math.abs(start - i) 4.Track minimum using Math.min() #Leetcode #DSA #Leetcode1848 #Java #Leetcodedailychallenge

Day 84 of #100DaysOfLeetCode 💻✅ Solved #567. Permutation in String problem in Java. Approach: * Used Sliding Window with frequency array * Decreased count for incoming characters * Adjusted window when count became invalid * Checked window size equal to s1 length Performance: ✓ Runtime: 6 ms (Beats 87.55% submissions) 🚀 ✓ Memory: 43.26 MB (Beats 99.80% submissions) Key Learning: ✓ Strengthened Sliding Window with frequency tracking ✓ Learned efficient permutation checking ✓ Improved handling of dynamic window adjustment Learning one problem every single day 🚀 #Java #LeetCode #DSA #SlidingWindow #Strings #Arrays #ProblemSolving #CodingJourney #100DaysOfCode

100 Days of Coding Challenge – Day 30 📌 Problem: Find the Index of the First Occurrence in a String 💻 Language: Java 🧠 Concept Used: String Matching (Brute Force) 🔍 Platform: LeetCode Today’s challenge was to find the first occurrence of a substring (needle) in a given string (haystack). If not found, return -1. Example: Input: "sadbutsad", "sad" Output: 0 Approach: ✔ Traverse the string from index 0 to n - m ✔ Extract substring of length m at each position ✔ Compare it with the target string ✔ Return index immediately when match is found ✔ If no match → return -1 Time Complexity: O(n × m) Space Complexity: O(1) 🔗 Problem Link: https://lnkd.in/g2ktYFFS 🔗 Code: https://lnkd.in/gynFixSQ #100DaysOfCode #Day30 #Java #DSA #LeetCode #Strings #ProblemSolving #CodingJourney

Day 85 of #100DaysOfLeetCode 💻✅ Solved #76. Minimum Window Substring problem in Java. Approach: * Used Sliding Window with character frequency array * Tracked required characters to match target string * Expanded window and reduced requirement count * Shrunk window to find minimum valid substring Performance: ✓ Runtime: 2 ms (Beats 99.94% submissions) 🚀 ✓ Memory: 45.51 MB (Beats 80.16% submissions) Key Learning: ✓ Mastered advanced Sliding Window technique ✓ Learned optimal substring minimization strategy ✓ Improved handling of variable window constraints Learning one problem every single day 🚀 #Java #LeetCode #DSA #SlidingWindow #Strings #HashMap #ProblemSolving #CodingJourney #100DaysOfCode

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