Lexicographically Largest String with One Swap

🚀 Day 34/180 | #180DaysOfCode 📍 LeetCode | 💻 Java Solved: 709. To Lower Case Used ASCII manipulation to convert uppercase letters to lowercase by adding 32, without using built-in functions. ⏱️ Time Complexity: O(n) 📦 Space Complexity: O(n) Strengthening understanding of character encoding and string manipulation basics. 💪 Consistency continues 🚀 #DSA #LeetCode #Java #CodingJourney #Consistency

Day 66 — LeetCode Progress (Java) Problem: Find the Difference of Two Arrays Required: Given two integer arrays, return: Elements present in nums1 but not in nums2 Elements present in nums2 but not in nums1 Idea: Use sets to remove duplicates and quickly check membership. Approach: Convert both arrays into sets Iterate over nums1 set: Add elements not present in nums2 set to result1 Iterate over nums2 set: Add elements not present in nums1 set to result2 Return both lists Time Complexity: O(n + m) Space Complexity: O(n + m) #LeetCode #DSA #Java #HashSet #Arrays #ProblemSolving #CodingJourney

Day 31/75 — Sum of Two Integers (Without + or -) Today's problem was about performing addition using bit manipulation. Key idea: • XOR (^) gives sum without carry • AND (&) + left shift gives carry Algorithm: while (b != 0): carry = (a & b) << 1 a = a ^ b b = carry Repeat until carry becomes zero. Time Complexity: O(1) Space Complexity: O(1) This problem gave a deeper understanding of how addition works at the binary level. 31/75 🚀 #Day31 #DSA #BitManipulation #Java #Algorithms #LeetCode

🚀 DSA Preparation 💪 Solved a simple yet important String + Sliding Window problem. Focused on checking unique characters in fixed-size substrings efficiently. Great practice for improving window-based pattern recognition 🔥 🧠 Problem 🔎 Substrings of Size Three with Distinct Characters Given a string s, return the number of good substrings of length 3. 👉 A substring is good if all characters are distinct. 👉 Count all such substrings (including duplicates if they appear multiple times). Example Input: s = "xyzzaz" Output: 1 Input: s = "aababcabc" Output: 4 Improving DSA with small patterns and clean logic 🚀 #DSA #LeetCode #Strings #SlidingWindow #Java #ProblemSolving #Consistency

Solved a problem where we need to check if two strings can be made equal using a special operation. The rule is: you can swap characters only if the distance between their positions is even. So basically, characters at even indices can only swap among themselves, and same for odd indices. Idea: Instead of actually swapping, I just counted characters separately for even and odd positions in both strings. If both match, then it’s possible — otherwise not. Simple concept, but interesting twist! 😊 #LeetCode #DSA #Java #ProblemSolving #CodingJourney

Day 45 of DSA🚀 🔹 Problem: Remove all occurrences of a given value from an array in-place and return the count of remaining elements. 🔹 Key Idea: Used the two-pointer technique to overwrite unwanted elements and keep valid ones at the beginning of the array. ✔ Time Complexity: O(n) ✔ Space Complexity: O(1) Small problems like this reinforce an important concept: in-place array manipulation without extra memory. #DSA #Java #LeetCode #CodingPractice #ProblemSolving

Day 56 of #100DaysOfLeetCode 💻✅ Solved #205. Isomorphic Strings problem in Java. Approach: • Used two arrays to track character mappings for both strings • Traversed both strings simultaneously • Checked if the mapping values at current characters are equal • If not equal, returned false (mapping mismatch) • Updated both arrays with the current index + 1 • This ensures consistent one-to-one mapping between characters Performance: ✓ Runtime: 8 ms (Beats 72.19% submissions) ✓ Memory: 44.16 MB (Beats 22.15% submissions) Key Learning: ✓ Learned how to maintain mapping consistency between two strings ✓ Practiced using arrays for character indexing ✓ Strengthened understanding of string pattern matching problems Learning one problem every single day 🚀 #Java #LeetCode #DSA #Strings #ProblemSolving #CodingJourney #100DaysOfCode

Day 88 - LeetCode Journey Solved LeetCode 24: Swap Nodes in Pairs in Java ✅ This problem is a great exercise in pointer manipulation in linked lists. Instead of changing values, I swapped the actual nodes by carefully adjusting the next pointers. Using a dummy node made the process much cleaner and helped handle edge cases smoothly. Step by step, I swapped pairs while moving forward in the list. Key takeaways: • Deep understanding of pointer manipulation • Importance of dummy node in linked list problems • Clean handling of edge cases • Iterative approach for swapping nodes ✅ All test cases passed ⚡ Efficient O(n) time and O(1) space Linked list problems like this really sharpen your fundamentals 🔥 #LeetCode #DSA #Java #LinkedList #Pointers #ProblemSolving #CodingJourney #InterviewPrep #Consistency #100DaysOfCode

🚀 𝐃𝐚𝐲 89/100 – 𝐈𝐬 𝐒𝐮𝐛𝐬𝐞𝐪𝐮𝐞𝐧𝐜𝐞 Today’s problem was 𝐈𝐬 𝐒𝐮𝐛𝐬𝐞𝐪𝐮𝐞𝐧𝐜𝐞 — a simple yet fundamental problem to understand two-pointer technique. 🔍 𝐊𝐞𝐲 𝐋𝐞𝐚𝐫𝐧𝐢𝐧𝐠: We can efficiently check if one string is a subsequence of another using two pointers. 💡 𝐂𝐨𝐫𝐞 𝐈𝐝𝐞𝐚: Traverse both strings Move pointer of s only when characters match Always move pointer of t  𝐖𝐡𝐲 𝐢𝐭 𝐰𝐨𝐫𝐤𝐬? We try to match characters of s in order within t without disturbing sequence. ⚡ 𝐀𝐩𝐩𝐫𝐨𝐚𝐜𝐡: Initialize two pointers i (for s) and j (for t) If characters match → move both Else → move only j If i reaches end of s → subsequence exists ⏱️ 𝐓𝐢𝐦𝐞 𝐂𝐨𝐦𝐩𝐥𝐞𝐱𝐢𝐭𝐲: 𝐎(𝐧) 📦 𝐒𝐩𝐚𝐜𝐞 𝐂𝐨𝐦𝐩𝐥𝐞𝐱𝐢𝐭𝐲: 𝐎(1) #Day89 #100DaysOfCode #Java #DSA #LeetCode #TwoPointers #CodingJourney

🚀100 Days of Code Day - 17 Problem Solved: Letter Combinations of a Phone Number Today I worked on an interesting backtracking problem where I generated all possible letter combinations from a given digit string (2–9), based on the classic phone keypad mapping. 🔍 Key Learnings: • Understood how recursion helps explore all possible combinations • Strengthened my knowledge of backtracking techniques • Improved problem-solving and logical thinking 💡Approach: Used a recursive backtracking method to build combinations step by step, exploring all possible letter mappings for each digit. 📌 Example: Input: "23" Output: ["ad","ae","af","bd","be","bf","cd","ce","cf"] This problem is a great example of how powerful recursion can be when dealing with combinations. #Java #DSA #Backtracking #ProblemSolving #CodingJourney #LeetCode