Hemali Chotalia’s Post

100 Days of Coding Challenge – Day 20 📌 Problem: Remove Duplicates from Sorted Array 💻 Language: Java 🧠 Concept Used: Two Pointer Technique 🔍 Platform: LeetCode Today’s challenge was to remove duplicates from a sorted array in-place while keeping the relative order of elements the same. Approach: ✔ Use two pointers — one to traverse the array and another to track the position of unique elements ✔ Compare the current element with the previous one ✔ If they are different, place the element at the next unique position ✔ Time Complexity: O(n) ✔ Space Complexity: O(1) 🔗 Problem Link: https://lnkd.in/g83THPD6 🔗 Code: https://lnkd.in/gmrtpCRT #100DaysOfCode #Day20 #Java #DSA #LeetCode #TwoPointers #Arrays #ProblemSolving #CodingJourney

🚀 Day 7 / 100 – LeetCode Challenge Today I solved Length of Last Word (LeetCode #58) using Java. 🔹 Problem: Given a string "s" containing words and spaces, return the length of the last word in the string. 📌 Approach: - Traverse the string from the end. - Ignore trailing spaces. - Start counting characters of the last word. - Stop when a space appears after counting begins. 💡 Key Concepts Practiced: - String traversal - "charAt()" usage - Reverse iteration - Conditional logic ⏱ Time Complexity: O(n) 📦 Space Complexity: O(1) ✅ Key Takeaway: Sometimes solving a problem becomes easier when we traverse the data from the end instead of the beginning. #100DaysOfCode #LeetCode #Java #DSA #ProblemSolving #CodingJourney

100 Days of Coding Challenge – Day 19 📌 Problem: Merge Sorted Array 💻 Language: Java 🧠 Concept Used: Array Manipulation + Sorting 🔍 Platform: LeetCode Today’s challenge was to merge two sorted arrays into a single sorted array. The result must be stored inside the first array (nums1). Approach: ✔ Copy elements from both arrays into a temporary array ✔ Place the combined elements back into nums1 ✔ Sort the final array to maintain non-decreasing order Time Complexity: O((m+n) log (m+n)) Space Complexity: O(m+n) 🔗 Problem Link: https://lnkd.in/gyFfUaiE 🔗 Code: https://lnkd.in/gA-MrnqG #100DaysOfCode #Day19 #Java #DSA #LeetCode #Arrays #ProblemSolving #CodingJourney

100 Days of Coding Challenge – Day 30 📌 Problem: Find the Index of the First Occurrence in a String 💻 Language: Java 🧠 Concept Used: String Matching (Brute Force) 🔍 Platform: LeetCode Today’s challenge was to find the first occurrence of a substring (needle) in a given string (haystack). If not found, return -1. Example: Input: "sadbutsad", "sad" Output: 0 Approach: ✔ Traverse the string from index 0 to n - m ✔ Extract substring of length m at each position ✔ Compare it with the target string ✔ Return index immediately when match is found ✔ If no match → return -1 Time Complexity: O(n × m) Space Complexity: O(1) 🔗 Problem Link: https://lnkd.in/g2ktYFFS 🔗 Code: https://lnkd.in/gynFixSQ #100DaysOfCode #Day30 #Java #DSA #LeetCode #Strings #ProblemSolving #CodingJourney

100 Days of Coding Challenge – Day 26 📌 Problem: Remove Duplicates from Sorted Array II 💻 Language: Java 🧠 Concept Used: Two Pointer Technique + Counting 🔍 Platform: LeetCode Today’s challenge was to remove duplicates from a sorted array in-place, but this time allowing at most two occurrences of each element. Approach: ✔ Traverse the array and track occurrences using a counter ✔ Allow elements to appear at most twice ✔ Use a pointer k to place valid elements in the correct position ✔ Skip elements when they exceed the allowed count Time Complexity: O(n) Space Complexity: O(1) 🔗 Problem Link: https://lnkd.in/gm2_CHbz 🔗 Code: https://lnkd.in/gKxuTbsG #100DaysOfCode #Day26 #Java #DSA #LeetCode #TwoPointers #Arrays #ProblemSolving #CodingJourney

100 Days of Coding Challenge – Day 23 📌 Problem: Longest Consecutive Sequence 💻 Language: Java 🧠 Concept Used: Sorting + Sequence Counting 🔍 Platform: LeetCode Today’s challenge was to find the length of the longest sequence of consecutive numbers in an unsorted array. The numbers do not need to be adjacent in the original array, but they must form a continuous sequence like 1,2,3,4. Example: Input: [100, 4, 200, 1, 3, 2] Output: 4 → Longest sequence: [1,2,3,4] Approach: ✔ First sort the array ✔ Traverse the array and check if the next number is consecutive ✔ Skip duplicates ✔ Track the longest streak using a counter Time Complexity: O(n log n) (due to sorting) Space Complexity: O(1) 🔗 Problem Link: https://lnkd.in/gguN6KnH 🔗 Code: https://lnkd.in/gyVFpsbg #100DaysOfCode #Day23 #Java #DSA #LeetCode #Arrays #ProblemSolving #CodingJourney

🚀 Day 99 of My 100 Days LeetCode Challenge | Java Today’s problem was all about randomization and linked list traversal — a nice break from heavy DP and matrices. The challenge was to design a system that returns a random node’s value from a singly linked list, ensuring that every node has an equal probability of being chosen. Since linked lists don’t allow direct indexing, the key idea was to first determine the size of the list, and then generate a random index to fetch the corresponding node. This approach ensures uniform randomness while keeping the implementation simple and efficient. ✅ Problem Solved: Linked List Random Node ✔️ All test cases passed (8/8) ⏱️ Runtime: 11 ms 🧠 Approach: Linked List Traversal + Randomization 🧩 Key Learnings: ● Randomization problems require ensuring uniform probability distribution. ● Linked lists limit direct access, so traversal becomes essential. ● Precomputing size can simplify random selection. ● Sometimes simple approaches are the most effective. ● Understanding data structure limitations helps design better solutions. This problem highlighted how probability + data structures can come together in elegant ways. 🔥 Day 99 complete — sharpening my understanding of randomization and linked list behavior. #LeetCode #100DaysOfCode #Java #LinkedList #Randomization #Algorithms #ProblemSolving #DSA #CodingJourney #Consistency

Day 57 of #100DaysOfLeetCode 💻✅ Solved #506. Relative Ranks problem in Java. Approach: • Iterated through each player's score • Compared it with all other scores to determine its rank • Increased rank whenever a higher score was found • Assigned medals for top 3 ranks: Gold, Silver, Bronze • Converted remaining ranks to string and stored in result array Performance: ✓ Runtime: 124 ms (Beats 5.06% submissions) ✓ Memory: 46.76 MB (Beats 99.84% submissions) Key Learning: ✓ Understood ranking logic using comparison ✓ Practiced nested loop approach for problem solving ✓ Learned the importance of optimizing time complexity Learning one problem every single day 🚀 #Java #LeetCode #DSA #Arrays #Sorting #ProblemSolving #CodingJourney #100DaysOfCode

🚀 Day 37/100 – LeetCode Challenge ✅ Problem Solved: 67. Add Binary 🟢 Difficulty: Easy 💻 Language: Java ⚡ Runtime: 1 ms (Beats 99.86%) Today’s problem was about adding two binary strings and returning their sum as a binary string. 🔎 Key Learning: Simulating binary addition manually (like elementary math addition) Handling carry properly Using StringBuilder for efficient string manipulation Traversing strings from right to left 🧠 Approach: Start from the last index of both strings Add digits along with carry Append sum % 2 to result Update carry as sum / 2 Reverse the result at the end 💡 Why this problem is important? It strengthens: String manipulation skills Understanding of number systems Edge case handling (different lengths, leftover carry) Consistency > Motivation. 37 days down, 63 to go! 💪🔥 #Day37 #100DaysOfCode #LeetCode #Java #ProblemSolving #CodingJourney #SoftwareEngineering #DSA

Day 63 of #100DaysOfLeetCode 💻✅ Solved #2085. Count Common Words With One Occurrence problem in Java. Approach: • Iterated through each word in the first array • Avoided duplicate checks by ensuring each word is processed only once • Counted occurrences of the current word in both arrays • If the word appears exactly once in both arrays, incremented the result • Returned the final count Performance: ✓ Runtime: 88 ms (Beats 7.45% submissions) ✓ Memory: 46.06 MB (Beats 93.07% submissions) Key Learning: ✓ Practiced handling duplicates and frequency counting ✓ Improved understanding of string comparison in arrays ✓ Learned importance of optimizing nested loop solutions Learning one problem every single day 🚀 #Java #LeetCode #DSA #Strings #Arrays #ProblemSolving #CodingJourney #100DaysOfCode