Max Substring Frequency with Constraints

🔥 DSA Challenge – Day 136/360 🚀 📌 Topic: Bit Manipulation 🧩 Problem: Number of 1 Bits (Hamming Weight) Problem Statement: Given an integer, return the number of set bits (1’s) present in its binary representation. 🔍 Example: Input: 6 Output: 2 Explanation: Binary of 6 → 110 → 2 set bits 💡 Optimized Approach (Brian Kernighan’s Algorithm): Instead of checking each bit one by one, we use a smart trick: n & (n - 1) removes the rightmost set bit in each iteration This reduces the number of operations to the number of set bits only ⚡ Time Complexity: O(k) (k = number of set bits) ⚡ Space Complexity: O(1) 🚀 Key Takeaway: Using bit manipulation can drastically optimize performance compared to brute force approaches. Always look for patterns in binary operations! #DSA #Coding #Java #BitManipulation #136DaysOfCode #LeetCode #ProblemSolving #SoftwareEngineering

🔥 DSA Challenge – Day 135/360 🚀 📌 Topic: Bit Manipulation 🧩 Problem: Check if a Number is Power of 2 Problem Statement: Given an integer n, determine whether it is a power of 2 or not. 🔍 Example: Input: n = 4 Output: true Input: n = 6 Output: false 💡 Approach: Optimized (Bit Manipulation) 1️⃣ Step 1 – If n <= 0, return false (powers of 2 are always positive) 2️⃣ Step 2 – Use bit trick: n & (n - 1) removes the lowest set bit 3️⃣ Step 3 – If result becomes 0, then only one set bit was present ✔ This avoids looping and works in constant time ⏱ Complexity: Time: O(1) Space: O(1) 📚 Key Learning: A number is a power of 2 if it has exactly one set bit in binary representation. #DSA #Java #Coding #InterviewPrep #ProblemSolving #TechJourney #135DaysOfCode #BitManipulation #LeetCode

🚀 Day 56 of #100DaysOfLeetCode Solved: Longest Substring Without Repeating Characters Today’s problem really tested my understanding of the sliding window technique. 🔹 Key Learning: Instead of restarting the window when a duplicate appears, I used a HashMap to track the last index of characters and moved the left pointer smartly using Math.max(). This helped maintain an optimal window without unnecessary rework. 🔹 Approach: Used two pointers (left & right) Stored last seen index of each character Adjusted window dynamically to avoid duplicates 🔹 Complexity: Time: O(n) Space: O(n) This problem made me realize how important it is to truly understand pointer movement rather than just memorizing patterns. Slowly building consistency and clarity, one problem at a time. #LeetCode #DSA #Java #CodingJourney #ProblemSolving #Consistency

Day 44 #SDE sliding window techniques and optimization problems. Solved: • Longest Substring Without Repeating Characters • Maximum Points You Can Obtain from Cards Key Learning: • “Longest Substring Without Repeating Characters” is a classic sliding window + hashing problem, where we dynamically adjust the window to maintain unique characters. • “Maximum Points from Cards” uses a clever window optimization, where instead of picking k cards directly, we minimize the sum of the remaining subarray. #LeetCode #DSA #SlidingWindow #Algorithms #Java #SoftwareEngineering

Day 41 #SDE stack-based validation and dynamic programming on strings. Solved: • Bracket Challenge • Word Break Key Learning: • “Bracket Challenge” reinforces the use of a stack to validate balanced parentheses and handle nested structures efficiently. • “Word Break” revisited the DP + memoization approach, where we check valid segmentations of a string using a dictionary. #LeetCode #DSA #Stack #DynamicProgramming #Algorithms #Java #SoftwareEngineering

Day 82 of DSA Journey Solved Isomorphic Strings today! This problem looks simple, but it teaches an important concept — one-to-one mapping between characters. 🔍 What I learned: Each character in one string must map to exactly one character in the other No two characters should map to the same character Consistency across the entire string is key 💡 Approach: Used two HashMaps to track mappings in both directions: s → t t → s This avoids conflicts and ensures correctness. 🧠 Example: "paper" → "title" ✅ "foo" → "bar" ❌ ✨ Key takeaway: Always think about bidirectional mapping when dealing with transformation problems. Small problem, but powerful concept! #DSA #Java #CodingJourney #100DaysOfCode #ProblemSolving

📊 DSA Progress Update – Week 5 Over the past few days, I’ve been practicing array problems and improving my approach step by step. What I learned: • Starting with a brute force solution helps in understanding the problem clearly • Optimization becomes easier once the pattern is identified • Key techniques : - Two Pointers - Sliding Window - Prefix Sum - Kadane’s Algorithm Something new: Started learning Binary Search and understanding its basic approach. Plan: Continue practicing and get more comfortable with these concepts. Taking it one step at a time. #DSA #Java #LeetCode #Consistency #CodingJourney

🚀 Day 13 – DSA Practice Today I explored the Sliding Window technique using the problem: Maximum Sum Subarray of Size K 📌 Problem: Given an array and a window size k, find the maximum sum of any subarray of size k. 💡 Approach: Instead of recalculating sum every time, maintain a window sum: • Add next element • Remove previous element This helps process the array in a single pass ⏱ Time Complexity: O(n) 📦 Space Complexity: O(1) This problem helped me understand how sliding window optimizes subarray problems efficiently. #Java #DSA #SlidingWindow #CodingInterview #ProblemSolving

DSA Practice Update Today I solved: #141 – Linked List Cycle Learned how to detect a cycle in a linked list using Floyd’s Cycle Detection Algorithm (fast and slow pointers). Understood how moving pointers at different speeds helps identify if a loop exists without using extra space. Key Learnings: • Fast and slow pointer technique • Detecting cycles efficiently in O(n) time • Solving problems with constant space complexity This problem strengthened my understanding of pointer-based approaches, which are commonly used in linked list interview questions. Continuing to stay consistent and improve problem-solving skills step by step. #DSA #LeetCode #CodingJourney #Java #SoftwareDevelopment #PlacementPreparation

🚀 Day 8 of #100DaysOfDSA Today’s problem: Longest Substring Without Repeating Characters 🧠 Problem Statement: Given a string, find the length of the longest substring without repeating characters. 💡 Approach: Sliding Window Technique Used two pointers (left & right) Maintained a HashSet to track characters Expanded window when unique Shrunk window when duplicate found ⚡ Key Learning: Efficient use of the sliding window helps reduce time complexity to O(n), which is crucial for optimizing string-based problems. 💻 Example: Input: "abcabcbb" Output: 3 ("abc") 🔥 This problem strengthened my understanding of: ✔️ Two-pointer technique ✔️ Hashing (Set/Map) ✔️ Optimizing brute force solutions Consistency is the key — small steps every day lead to big results 💪 #DSA #Java #CodingJourney #LeetCode #ProblemSolving #100DaysOfCode 🍁 Saidhanya Sree