Minimize Max Pair Sum in Array with Sorting and Pointers

🔹 Day 85 – #100DaysOfLeetCode Problem: 3010. Divide an Array Into Subarrays With Minimum Cost I Difficulty: Easy Key Insight: The cost of a subarray depends only on its first element. Since the first subarray always starts at index 0, the problem reduces to selecting the two smallest possible starting elements from the remaining array. Approach: Fix the first subarray cost as nums[0] Find the smallest and second smallest values in nums[1…n-1] Add them to get the minimum total cost Time Complexity: O(n) Space Complexity: O(1) #LeetCode #Java #ProblemSolving #CodingChallenge #100DaysOfCode #DSA #LearningEveryday

📌 LeetCode Day 38/50 – Linked List Cycle Today’s problem was about detecting a cycle in a linked list. The challenge was to determine whether a linked list contains a loop without using extra memory. 🔍 Approach Used: Used two pointers moving at different speeds If a cycle exists, both pointers will eventually meet This approach runs in O(n) time and O(1) space 💡 Key Takeaway: Understanding pointer movement patterns helps solve complex linked list problems efficiently. 🚀 Consistency is the key — one problem a day brings clarity and confidence! #LeetCode #Day38 #50DaysOfLeetCode #LinkedList #FloydsAlgorithm #DSA #Java #CodingChallenge #Consistency #ProblemSolving

🚀 Day 95 of #100DaysOfLeetCode 📌 Problem 216. Combination Sum III 🟡 Difficulty Medium 🛠️ Approach Use a recursive backtracking function. Maintain: k → numbers left to pick n → remaining sum start → next number to try (to avoid duplicates) ans → current combination If k == 0 and n == 0, add the combination to result. Iterate from start to 9, pick number, recurse, then backtrack. #LeetCode #Java #ProblemSolving #CodingChallenge #100DaysOfCode #DSA #LearningEveryday

Day #42/100 Days of Code🔥 Solved #LeetCode 61: 𝐑𝐨𝐭𝐚𝐭𝐞 𝐋𝐢𝐬𝐭 𝐭𝐨𝐝𝐚𝐲  Focused on understanding linked list manipulation, edge cases, and optimizing the approach to 𝐎(𝐧) 𝐭𝐢𝐦𝐞 & 𝐎(1) 𝐬𝐩𝐚𝐜𝐞. Key takeaways: Always handle 𝐤 % 𝐥𝐞𝐧𝐠𝐭𝐡 in rotation problems Turning the list into a circular linked list simplifies logic #100DaysOfCode #LeetCode #DSA #LinkedList #Java #ProblemSolving #Consistency #LearningJourney

Day 20/100 – LeetCode Challenge 🚀 Problem: Subsets (Power Set) Approach: Started with an empty subset For each number in the array, created new subsets by adding the number to all existing subsets Appended the newly formed subsets to the result list Time Complexity: O(n × 2ⁿ) Space Complexity: O(n × 2ⁿ) (to store all subsets) Key takeaway: Many combinatorial problems can be solved by building results incrementally, expanding previously generated subsets. #LeetCode #100DaysOfCode #DSA #Java #ProblemSolving #Backtracking #100DaysOfLeetCode

🚀 Day 99 of #100DaysOfLeetCode 📌 Problem: 67. Add Binary 📊 Difficulty: Easy 💡 Key Insight: Binary addition follows the same rules as decimal addition — add digits from right to left while maintaining a carry. The only difference is everything is in base 2. 🛠️ Approach: Use two pointers starting from the end of both strings Add corresponding bits along with a carry Append the result bit (sum % 2) Update carry (sum / 2) Reverse the final string to get the answer ⏱️ Complexity: Time: O(n) Space: O(n) #LeetCode #Java #ProblemSolving #CodingChallenge #100DaysOfCode #DSA #LearningEveryday

Day 8/100 – LeetCode Challenge 🚀 Problem: Implement strStr() Approach: Checked every possible starting index in haystack Matched characters one by one with needle Time Complexity: O(n × m) Space Complexity: O(1) Key takeaway: Brute-force solutions are fine when constraints allow them. Understanding the basic approach comes before optimization. #LeetCode #100DaysOfCode #DSA #Java #ProblemSolving #100DaysOfLeetCode

Day 25/100 – LeetCode Challenge 🚀 Problem: Plus One Approach: Traversed digits from right to left Handled carry when the digit was 9 Created a new array only when all digits were 9 Time Complexity: O(n) Space Complexity: O(1) Key takeaway: Many array problems that involve arithmetic operations require careful carry handling from the end of the array. #LeetCode #100DaysOfCode #DSA #Java #ProblemSolving #InterviewPrep

Day 13/100 – LeetCode Challenge 🚀 Solved Count Binary Substrings using an optimized O(n) approach by grouping consecutive characters and comparing segment lengths. Key takeaway: Instead of generating all substrings, identify patterns and reduce the problem to counting adjacent groups. Consistency > Motivation 💪 #100DaysOfCode #DSA #Java #LeetCode

Day: 43/365 📌 LeetCode POTD: Binary Number with Alternating Bits Easy Key takeaways/Learnings from this problem: 1. This one shows how clean bit tricks can replace messy string checks when working with binary patterns. 2. Big takeaway: sometimes a small observation (like using XOR or shifting) turns a pattern problem into a super neat one-liner. #POTD #365DaysOfCode #DSA #Java #ProblemSolving #LearningInPublic #Consistency 🥷