Solved Matrix Diagonal Sum in Java for #100DaysOfLeetCode

🌟 Problem 21 – Merge Two Sorted Lists I solved this problem today on LeetCode 💪. It helped me understand how to work with linked lists and how to merge them efficiently. 🧩 Description: Given two sorted linked lists, merge them into one sorted list and return its head. 👉 Example: Input: list1 = [1,2,4], list2 = [1,3,4] Output: [1,1,2,3,4,4] ✅ Approach: * Compare nodes from both lists one by one. * Add the smaller value to the new list. * Continue until all elements are merged. 📈 Time Complexity: O(n + m) 📦 Space Complexity: O(1) #LeetCode #TopInterview150 #Java #DSA #Coding #ProblemSolving #LinkedList

🚀 Day 63 of My LeetCode journey 🚀 Problem : Custom Sort String Today’s problem was interesting because instead of sorting using normal alphabetical order, we sort the given string based on a custom priority order. 🧠 Problem Understanding Given: order → defines priority of characters. str → the input string which needs to be rearranged. Goal: ✅ Arrange characters of str based on the sequence defined in order. ✅ Characters not present in order should appear at the end (any order). 💡 Approach (Simple & Efficient) Count frequency of each character in str. First append characters following the order. Then append remaining characters. Time Complexity: O(n) Space Complexity: O(1) (fixed array size for 26 letters) ✨ Learnings Sometimes the problem isn't about sorting, but about following a custom priority. Frequency counting is extremely powerful for character-based problems. StringBuilder → best way to build strings efficiently in Java. #leetcode #coding #dsa #java #100DaysOfCode #day63 #learningEveryday #problemSolving

💡 LeetCode #58 — Length of Last Word Today I solved LeetCode Problem 58: Length of Last Word 🧠 Problem Summary: Given a string s consisting of words and spaces, return the length of the last word in the string. A word is defined as a sequence of non-space characters. Key Idea: We can traverse the string from end to start — Skip trailing spaces. Count the number of characters until the next space (which marks the last word). This avoids unnecessary splitting and saves extra space. #LeetCode #Java #DSA #Strings #ProblemSolving #CodingChallenge

#100DaysOfCode – Day 74 Count and Say Problem: Given an integer n, return the n-th term of the “Count and Say” sequence a fascinating pattern where each term describes the previous one. Example: Input: n = 4 Output: "1211" My Approach: Used recursion to generate the previous term. Applied run-length encoding logic counted consecutive digits and built the next term using a StringBuilder. Optimized for clean, readable iteration with O(N²) complexity (due to string building). Understanding recursive string construction deepens how we visualize “generation-based” sequences it’s not just about coding, it’s about seeing patterns grow. #100DaysOfCode #Java #LeetCode #ProblemSolving #Recursion #StringManipulation #CodingJourney #TechWithPurpose #takeUforward

🚀 Day 33 of My Daily Coding Challenge 🚀 Today I implemented and revised Cyclic Sort (Java) — one of the most efficient sorting techniques for arrays containing numbers from 1 to N. 💡 Key takeaway: Instead of comparing adjacent elements, Cyclic Sort keeps placing each number at its correct index — making it super fast for such problems. 🔗 Solution: [https://lnkd.in/epUjThMt] Building consistency, one algorithm at a time 💻💪 #DailyCodingChallenge #Java #DSA #CyclicSort #SortingAlgorithms #100DaysOfCode #LearningEveryday

💡 LeetCode 1929 – Concatenation of Array 💡 Today, I solved LeetCode Problem #1929: Concatenation of Array, a simple yet satisfying problem that tests your understanding of array manipulation and indexing in Java. ⚙️📊 🧩 Problem Overview: You’re given an integer array nums. Your task is to create a new array ans such that ans = nums + nums (i.e., concatenate the array with itself). 👉 Example: Input → nums = [1,2,1] Output → [1,2,1,1,2,1] 💡 Approach: 1️⃣ Find the length n of the given array. 2️⃣ Create a new array of size 2 * n. 3️⃣ Loop through nums once — place each element both at index i and index n + i. 4️⃣ Return the resulting array. ⚙️ Complexity Analysis: ✅ Time Complexity: O(n) — Single traversal of the array. ✅ Space Complexity: O(n) — For the concatenated array. ✨ Key Takeaways: Practiced index manipulation and array construction. Reinforced the importance of efficient iteration. A great warm-up problem that strengthens logical thinking and array fundamentals. 🌱 Reflection: Even the simplest problems build the foundation for solving more complex ones. Every bit of consistent practice helps in mastering problem-solving and clean coding habits. 🚀 #LeetCode #1929 #Java #ArrayManipulation #DSA #CodingJourney #CleanCode #ProblemSolving #AlgorithmicThinking #ConsistencyIsKey

🚀 Day 62/100 of #100DaysOfLeetCode Today’s challenge was “Happy Number” (LeetCode Problem 202). The task was to determine whether a given number is a Happy Number — meaning that by repeatedly replacing the number with the sum of the squares of its digits, the process eventually reaches 1. 💡 Key Takeaways: Strengthened understanding of pointer movement logic. Improved implementation skills using mathematical and logical thinking in Java. #100DaysOfCode #LeetCode #Java #CodingChallenge #ProblemSolving #DataStructures #Algorithms

💻 LeetCode Challenge – Day 6: Merge Two Sorted Lists Today’s challenge was all about linked lists — merging two sorted lists into one sorted list 🔗 🔹 Problem: Given two sorted linked lists, merge them into a single sorted linked list and return it. 🔹 Key Learnings: ✅ Deepened understanding of linked list traversal and pointers ✅ Practiced building a dummy node approach for cleaner logic ✅ Learned how to handle edge cases efficiently ✅ Reinforced the importance of iterative vs recursive thinking This problem really helped me think more clearly about data structure manipulation and clean code design. 💪 #LeetCode #100DaysOfCode #Java #CodingChallenge #ProblemSolving #LinkedList #MergeTwoSortedLists #CodingJourney

🚀 Day 43 of #100DaysOfLeetCode Today's problem: LeetCode #160 – Intersection of Two Linked Lists 💡 Concept: Find the node where two singly linked lists intersect. Used the Two Pointer Approach — a smart and efficient way to solve this without using extra memory. 🧠 Logic: Move both pointers through the lists. When one pointer reaches the end, switch it to the other list’s head. They’ll either meet at the intersection node or end up as null together. ✅ Complexity: Time – O(n + m) Space – O(1) 💬 Takeaway: Sometimes, the best solutions come from balancing the path — literally! Understanding how pointers sync up teaches a lot about memory references and linked list behavior. #LeetCode #CodingChallenge #Java #DataStructures #TwoPointerTechnique #ProblemSolving #LinkedLists

💻 LeetCode Challenge – Day 5: String to Integer (atoi) Today's problem was all about converting a string into an integer — seems simple, but the edge cases make it tricky! 🧠 🔹 Problem: Implement the atoi function, which converts a string to a 32-bit signed integer (just like in C/C++). 🔹 Key Learnings: ✅ Handling whitespaces and optional '+' or '-' signs ✅ Managing non-digit characters gracefully ✅ Preventing integer overflow & underflow ✅ Importance of clean parsing logic This problem really improved my understanding of string manipulation and boundary conditions in Java. 🚀 #LeetCode #100DaysOfCode #Java #CodingChallenge #ProblemSolving #StringToInteger #CodingJourney