Optimized Two Sum Solution in O(n) Time

Solved Add Two Numbers using linked lists. At first, the pointer-based structure was confusing, but breaking it down into simple steps made it manageable. Approach: Traverse both linked lists Add digits one by one Maintain carry (just like normal addition) Build a new linked list for the result #DSA #LinkedList #CPP #Coding

🗓 Day 9/100 – DSA Challenge Problem: Maximum Product of Two Elements in an Array (LeetCode #1464) 🎯 Goal: Find the maximum value of (nums[i] - 1) * (nums[j] - 1) for two different indices. 💡 Key Notes: Brute Force: Check all pairs → O(n2) O(n2) Optimized: Find top 2 largest numbers in one pass → O(n) O(n) Handles negative values and duplicates. Growing one problem at a time 💪 #100DaysOfCode #LeetCode #DSA #CodingChallenge

Day 14 Today, I continued my DSA practice on LeetCode and solved a design-based problem. I solved the "Implement Stack using Queues" problem using C++, and my solution passed all test cases. This problem helped me practice: • Understanding Stack vs Queue (LIFO vs FIFO) • Using queues to simulate stack behavior • Designing efficient data structures Problem: Implement a Last-In-First-Out (LIFO) stack using only two queues. The implemented stack should support all standard operations: • push(x) → Push element onto stack • pop() → Remove the top element • top() → Get the top element • empty() → Check if the stack is empty You must use only standard queue operations. Example: Input: ["MyStack","push","push","top","pop","empty"] [[],[1],[2],[],[],[]] Output: [null,null,null,2,2,false] Explanation: Stack follows LIFO, so the last pushed element is removed first. #Coding #CPP #DSA #Stack #Queue #ProblemSolving #LearningJourney #LeetCode #Consistency #ChandigarhUniversity #GDG

Understanding Lowest Common Ancestor (LCA) made simple. From recursion basics to real-world use cases like file systems and Git merges. 👉 Whenever you see a hierarchy and need a common parent — think LCA. #DSA #Algorithms #Coding #SystemDesign #Recursion

Day 22/75 🚀 Solved Determine if Two Strings Are Close (LeetCode 1657) today! ✅ All 169/169 test cases passed ⚡ Runtime: 6 ms (Beats ~75%) 💾 Memory: 23.30 MB (Beats ~94%) 🔍 Approach: First checked if both strings have equal length. Counted character frequencies using two arrays of size 26. Ensured: ✔️ Both strings use the same set of characters ✔️ Character frequency patterns can be rearranged to match If both conditions pass → strings are “close.” 💡 Key Learning: Understanding constraints and allowed operations helps simplify complex-looking problems. Here, it’s all about comparing character presence and frequency patterns, not actual character positions. Consistency + clarity = stronger problem-solving 💪 #LeetCode #CPP #DSA #ProblemSolving #CodingJourney #75DaysOfCode #Focused

Day-28 Solved the Count and Say problem today and it turned out to be a really good exercise in string manipulation. 👉 The idea is simple: start with "1" and keep generating the next term by describing the previous one. 👉 You only count consecutive digits, not overall frequency. 👉 Example: "1" → "11" → "21" → "1211" 💡 What I learned: Always think in terms of patterns Handle edge cases carefully (especially index bounds ⚠️) Small bugs like accessing i+1 without checking can break everything 🛠️ Concepts used: Strings Loops to_string() It looked confusing at first, but once the pattern clicked, it became straightforward. #leetcode #cpp #dsa #coding #learning

Day 18/160 of my DSA journey 🚀 Today I solved the Search Pattern (KMP Algorithm) problem. This problem focused on finding all occurrences of a pattern in a text efficiently. 💡 Key Insight: Instead of checking every position (O(n·m)), I used the KMP algorithm, which uses an LPS (Longest Prefix Suffix) array to skip unnecessary comparisons. Build LPS array for the pattern Use it to avoid re-checking matched characters Achieve linear time complexity This reduces complexity to O(n + m), which is crucial for large inputs. 📌 Also reinforced the concept of: Pattern matching optimization Prefix-suffix relationships Avoiding redundant comparisons Consistency is the real game 💪 #Day18 #DSA #GeeksforGeeks #CodingJourney #100DaysOfCode #ProblemSolving #Java #Algorithms #Coding #LearnToCode #TechJourney

💡 Day 213 ✅ Longest Subarray with Sum = K (Quick Insight) Use Prefix Sum + HashMap to solve in O(n) ⚡ Key Points Store first occurrence of prefix sum Works with negative numbers Sliding window ❌ (not reliable here) #DSA #Coding #LeetCode #LongestSubarraywithSumequaltoK