3Sum Problem Solved with Two-Pointer Technique

🚀 Day 17/60 — LeetCode Discipline Problem Solved: 4Sum (Revision) Difficulty: Medium Today’s session revisited the classic k-Sum family problem — 4Sum. After solving 2Sum and 3Sum patterns previously, this problem naturally extends the idea by combining sorting with nested iteration and the two-pointer technique to efficiently identify unique quadruplets. The key challenge lies in managing duplicates carefully while keeping the solution efficient and structured. 💡 Focus Areas: • Strengthened k-Sum pattern understanding • Practiced sorting + two-pointer combination • Improved duplicate handling in multi-pointer problems • Reinforced nested iteration optimization • Focused on writing structured and readable code Problems like these highlight how mastering one pattern allows you to scale the same idea to more complex variations. #LeetCode #60DaysOfCode #100DaysOfCode #DSA #TwoPointers #Arrays #Algorithms #DataStructures #ProblemSolving #CodingJourney #SoftwareEngineering #Programming #Developers #TechCareers

🚀 Day 9/60 — LeetCode Discipline Problem Solved: Container With Most Water (Revision) Difficulty: Medium Today’s session focused on revisiting this classic two-pointer optimization problem. The key insight was understanding how intelligently moving pointers can reduce time complexity while still exploring the optimal solution space. 💡 Focus Areas: • Strengthened two-pointer optimization technique • Improved area maximization intuition • Practiced greedy pointer movement logic • Focused on writing clean and efficient implementation ⚡ Performance Highlight: Achieved ~81% runtime efficiency on submission. Steady practice. Sharper instincts. Stronger foundations. #LeetCode #60DaysOfCode #100DaysOfCode #DSA #TwoPointers #Greedy #Algorithms #DataStructures #ProblemSolving #CodingJourney #SoftwareEngineering #TechCareers #Programming #Developers #CodingLife

🚀 Day 13/60 — LeetCode Discipline Problem Solved: Contains Duplicate II (Revision) Difficulty: Easy Today’s practice focused on revisiting a classic array problem that blends hashing with a sliding window concept. The goal was to efficiently determine whether duplicate values appear within a specific index range. Instead of checking every possible pair, the approach maintains a moving window of elements using a hash structure, allowing constant-time lookups while traversing the array. 💡 Focus Areas: • Reinforced hash-based lookup techniques • Practiced sliding window with bounded size • Strengthened index-distance reasoning • Improved understanding of time-efficient duplicate detection • Focused on clean and readable implementation Even simple problems can reinforce powerful ideas when approached with discipline and clarity. #LeetCode #60DaysOfCode #100DaysOfCode #DSA #SlidingWindow #HashSet #Arrays #Algorithms #DataStructures #ProblemSolving #CodingJourney #SoftwareEngineering #Programming #Developers

🚀 Day 181 of #200DaysOfCoding Today I solved “Minimum Changes To Make Alternating Binary String” on LeetCode. 🔹 Problem: We are given a binary string consisting of 0 and 1. In one operation, we can flip any character (0 → 1 or 1 → 0). The goal is to make the string alternating, meaning no two adjacent characters are the same. Example of alternating strings: 0101, 1010 🔹 Key Insight: An alternating binary string can only have two possible patterns: 1️⃣ 010101... 2️⃣ 101010... So the idea is simple: Count how many changes are needed to convert the string to pattern 1. Count how many changes are needed to convert it to pattern 2. The minimum of the two will be the answer. ⏱ Time Complexity: O(n) 📦 Space Complexity: O(1) Consistent practice is helping me improve my problem-solving and pattern recognition skills every day. #leetcode #coding #programming #cpp #100daysofcode #200daysofcoding #softwaredevelopment

Day 47 on LeetCode — Partition Labels ✂️✅ Today’s problem was a great example of greedy strategy with smart indexing. 🔹 Approach Used in My Solution The goal was to split the string into maximum number of partitions such that each character appears in only one part. Key idea in the solution: • First, store the last occurrence of each character in an array • Traverse the string while maintaining a current partition range • Continuously update the end of the partition using the last index of characters encountered • When the current index reaches end, it means the partition is complete • Store the partition size and start a new one This greedy approach ensures each partition is as small as possible while still valid. ⚡ Complexity: • Time Complexity: O(n) • Space Complexity: O(1) 💡 Key Takeaways: • Learned how preprocessing (last occurrence tracking) simplifies problems • Practiced greedy partitioning techniques • Strengthened understanding of interval expansion logic #LeetCode #DSA #Algorithms #DataStructures #GreedyAlgorithm #Strings #ProblemSolving #Coding #Programming #Cpp #STL #SoftwareEngineering #ComputerScience #CodingPractice #DeveloperLife #TechJourney #CodingDaily #100DaysOfCode #BuildInPublic #AlgorithmPractice #CodingSkills #Developers #TechCommunity #SoftwareDeveloper #EngineeringJourney

🚀 Day 16/60 — LeetCode Discipline Problem Solved: Palindrome Number (Revision) Difficulty: Easy Today’s practice revisited a classic number-based problem — determining whether a given integer reads the same forward and backward. Even though the problem appears simple, it reinforces an important concept: recognizing symmetry in data and applying straightforward transformations to verify it efficiently. In this revision, the focus was on converting the integer into a comparable structure and checking whether the reversed representation matches the original value. 💡 Focus Areas: • Reinforced palindrome symmetry concepts • Practiced number-to-string transformations • Strengthened basic logical validation techniques • Focused on writing clear and readable code Consistent practice of even the simplest problems helps keep fundamental logic sharp and reliable. #LeetCode #60DaysOfCode #100DaysOfCode #DSA #Algorithms #ProblemSolving #Programming #CodingJourney #SoftwareEngineering #Developers #TechCareers

Day 50 on LeetCode — Maximum Average Subarray I 📊✅ Half-century milestone! 🚀 Today’s problem was a classic and clean application of the Sliding Window technique. 🔹 Approach Used in My Solution The goal was to find the maximum average of a subarray of size k. Key idea in the solution: • First, compute the sum of the first window of size k • Then slide the window forward by:   – Adding the next element   – Removing the element leaving the window • Continuously update the maximum sum encountered • Finally, divide the maximum sum by k to get the result This avoids recomputing sums and ensures an efficient solution. ⚡ Complexity: • Time Complexity: O(n) • Space Complexity: O(1) 💡 Key Takeaways: • Mastered the fixed-size sliding window pattern • Learned how to optimize subarray sum problems • Reinforced thinking in terms of window reuse instead of recomputation #LeetCode #DSA #Algorithms #DataStructures #SlidingWindow #Arrays #ProblemSolving #Coding #Programming #Cpp #STL #SoftwareEngineering #ComputerScience #CodingPractice #DeveloperLife #TechJourney #CodingDaily #100DaysOfCode #BuildInPublic #AlgorithmPractice #CodingSkills #Developers #TechCommunity #SoftwareDeveloper #EngineeringJourney

🚀 19 of #100DaysOfCode Solved LeetCode 1456 – Maximum Number of Vowels in a Substring of Given Length today. 🔍 Approach: Used the Sliding Window Technique to efficiently track the number of vowels in a substring of size k. Instead of recalculating vowels for every substring, we adjust the count as the window slides forward. 💡 Key Idea: Add the new character entering the window. Remove the character leaving the window. Keep track of the maximum vowel count. ⏱ Time Complexity: O(n) 📦 Space Complexity: O(1) This approach optimizes the brute-force solution and makes the algorithm scalable for large inputs. Consistent practice is helping me strengthen my problem-solving and data structures fundamentals. #leetcode #dsaalgorithms #slidingwindow #cpp #codingpractice #programming #softwaredevelopment #100daysofcode #developers #techlearning

Just solved a challenging binary tree problem! 🌳💻 🔍 Problem: Given a binary tree and an integer k, find the number of downward-only paths where the sum of node values equals k. ➡️ Paths can start and end at any node, but must always move from parent to child. 💡 Key Insight: Using prefix sum + hashmap during DFS traversal helps efficiently track all valid paths in O(n) time! ✅ All test cases passed ⚡ Optimized approach 🔥 Consistency streak continues! #geekstreak #gfg #npci #coding #dsa #binarytree #algorithms #100DaysOfCode #programming #developers #techgrowth

Day 38 on LeetCode — Brick Wall ✅ Today’s challenge focused on prefix sums and hash maps to minimize edge crossings. 🔹 Brick Wall The goal was to draw a vertical line that crosses the least number of bricks. Instead of checking every possible position, the optimized idea was to track edge positions of bricks (excluding the rightmost edge) using a hash map. By computing the prefix sum of brick widths in each row, we counted how many times a particular edge appears. The position with the maximum edge frequency means the line passes through gaps between bricks, resulting in fewer bricks crossed. ⚡ Complexity: • Time Complexity: O(n × m) • Space Complexity: O(n) 💡 Key Takeaways: • Learned how prefix sums help track cumulative positions • Applied hash maps for frequency counting • Practiced optimizing problems by transforming the perspective of the task #LeetCode #DSA #Algorithms #DataStructures #HashMap #PrefixSum #ProblemSolving #Coding #Programming #Cpp #STL #SoftwareEngineering #ComputerScience #CodingPractice #DeveloperLife #TechJourney #CodingDaily #100DaysOfCode #BuildInPublic #AlgorithmPractice #CodingSkills #Developers #TechCommunity #SoftwareDeveloper #EngineeringJourney