Check Binary String for Single Segment of Ones

Day 8 Today I solved “Check if Binary String Has at Most One Segment of Ones” on LeetCode. At first glance, the problem looks simple: Given a binary string, check whether it contains only one continuous segment of '1's. Example: "110" → Valid (one segment of 1s) "1001" → Invalid (two separate segments of 1s) While solving it, I realized an interesting observation: 👉 If a binary string has more than one segment of 1s, the pattern "01" must appear before another "1". So instead of counting segments explicitly, we can simply check whether '01' appears and is followed by another '1'. This turns the problem into a very efficient linear scan with O(n) time complexity. 💡 Key takeaway: Sometimes the simplest solution comes from recognizing patterns in the string rather than simulating the whole process. Also happy to see my solution running at 0 ms runtime (100% faster) 🚀 #LeetCode #DSA #ProblemSolving #Java #CodingJourney #BinaryStrings

💡 Day 41 of LeetCode Problem Solved! 🔧 🌟28. Find the Index of the First Occurrence in a String🌟 Task : • Given two strings needle and haystack, return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. Example 1: Input: haystack = "sadbutsad", needle = "sad" Output: 0 Explanation: "sad" occurs at index 0 and 6. The first occurrence is at index 0, so we return 0. Example 2: Input: haystack = "leetcode", needle = "leeto" Output: -1 Explanation: "leeto" did not occur in "leetcode", so we return -1. #LeetCode #Java #DSA #ProblemSolving #Consistency #100DaysOfChallenge #CodingJourney #KeepGrowing

Day 41 - Find Pivot Index Solved using a prefix sum approach. First computed the total sum of the array, then traversed once while maintaining a running left sum. For each index, the right sum is calculated using total - left - nums[i]. If both sums match, that index is the pivot. Time Complexity: O(n) #Day41 #LeetCode #Java #PrefixSum #DSA #ProblemSolving #CodingJourney

Solved a problem where we need to check if two strings can be made equal using a special operation. The rule is: you can swap characters only if the distance between their positions is even. So basically, characters at even indices can only swap among themselves, and same for odd indices. Idea: Instead of actually swapping, I just counted characters separately for even and odd positions in both strings. If both match, then it’s possible — otherwise not. Simple concept, but interesting twist! 😊 #LeetCode #DSA #Java #ProblemSolving #CodingJourney

Day 31/75 — Sum of Two Integers (Without + or -) Today's problem was about performing addition using bit manipulation. Key idea: • XOR (^) gives sum without carry • AND (&) + left shift gives carry Algorithm: while (b != 0): carry = (a & b) << 1 a = a ^ b b = carry Repeat until carry becomes zero. Time Complexity: O(1) Space Complexity: O(1) This problem gave a deeper understanding of how addition works at the binary level. 31/75 🚀 #Day31 #DSA #BitManipulation #Java #Algorithms #LeetCode

𝐃𝐚𝐲 87/100 – 𝐋𝐞𝐞𝐭𝐂𝐨𝐝𝐞 𝐂𝐡𝐚𝐥𝐥𝐞𝐧𝐠𝐞 🚀 Problem: 228. 𝐒𝐮𝐦𝐦𝐚𝐫𝐲 𝐑𝐚𝐧𝐠𝐞𝐬  Today I solved a problem where we need to summarize consecutive numbers in a sorted unique array into ranges. 🔑 𝐈𝐝𝐞𝐚: Traverse the array and keep extending the range while consecutive numbers continue. Once the sequence breaks, close the range and store it. 💡 𝐀𝐩𝐩𝐫𝐨𝐚𝐜𝐡: Start with the first element as start Move forward while nums[i] + 1 == nums[i+1] If range exists → "start->end" Else → single number "start" 𝐊𝐞𝐲 𝐈𝐧𝐬𝐢𝐠𝐡𝐭: Efficient single pass solution (O(n)) by grouping consecutive elements on the fly. #LeetCode #Java #ProblemSolving #DSA #100DaysOfCode #CodingJourney

🚀 Day 39 of #100DaysOfCode Solved 80. Remove Duplicates from Sorted Array II on LeetCode 🔢 🧠 Key Insight: The array is already sorted, and we need to ensure that each element appears at most twice, modifying the array in-place. ⚙️ Approach: 🔹Maintain a pointer i representing the position to place the next valid element 🔹Start iterating from index 2 🔹For each element nums[j], compare it with nums[i] 🔹If they are different, place the element at nums[i + 2] and move the pointer forward This ensures that no element appears more than twice while maintaining the sorted order. ⏱️ Time Complexity: O(n) 📦 Space Complexity: O(1) #100DaysOfCode #LeetCode #DSA #Arrays #TwoPointers #Java #ProblemSolving #InterviewPrep #LearningInPublic

Solved "Container With Most Water" on LeetCode today using the Two-Pointer Technique. 🚀 The key insight is that the area formed by two lines depends on the shorter height and the distance between them. Starting with pointers at both ends of the array, we compute the area and move the pointer at the smaller height inward to potentially find a taller boundary and maximize the area. This approach efficiently reduces the problem from O(n²) brute force to O(n) time with O(1) space. Problems like this are a great reminder that the right observation can drastically optimize a solution. 💡 #LeetCode #DSA #TwoPointers #Java #ProblemSolving

LeetCode 83 — Remove Duplicates from Sorted List This problem gives the head of a sorted linked list and asks to remove all duplicate values so that each element appears only once. Since the list is already sorted, duplicate values always appear next to each other. The task is simply to skip repeated nodes while keeping the original order of the list. Example : Input : 1 → 1 → 2 → 3 → 3 Output : 1 → 2 → 3 Approach used — Single Pass Pointer Traversal Because the list is sorted, the solution can be done in one traversal. Two pointers are used during traversal : - One pointer (a) keeps track of the last unique node. - Another pointer (b) scans the list forward. When both nodes have the same value, the duplicate node is skipped. When a new value appears, the unique node is connected to it. At the end, the last node’s next pointer is set to null to ensure the list ends correctly. This approach works in O(n) time and O(1) extra space. #leetcode #datastructures #linkedlist #java #problemSolving

🚀 Day 58 of #100DaysOfCode Solved 165. Compare Version Numbers on LeetCode 🔗 🧠 Key Insight: Version strings are split by "." into multiple revisions. We compare each revision numerically (not lexicographically). Example: "1.01" = "1.1" (leading zeros don’t matter) ⚙️ Approach (Split + Compare): 1️⃣ Split both versions using "." 🔹 version1 → s1[] 🔹 version2 → s2[] 2️⃣ Traverse till max length of both arrays 3️⃣ For each index i: 🔹 num1 = i < s1.length ? parseInt(s1[i]) : 0 🔹 num2 = i < s2.length ? parseInt(s2[i]) : 0 4️⃣ Compare: 🔹 if num1 < num2 → return -1 🔹 if num1 > num2 → return 1 5️⃣ If all equal → return 0 ⏱️ Time Complexity: O(n + m) 📦 Space Complexity: O(n + m) (for split arrays) #100DaysOfCode #LeetCode #DSA #Strings #TwoPointers #Java #InterviewPrep #CodingJourney