Flipping an Image in 100 Days of LeetCode Challenge

✅ Day 88 of 100 Days LeetCode Challenge Problem: 🔹 #1252 – Cells with Odd Values in a Matrix 🔗 https://lnkd.in/g5eE9A-e Learning Journey: 🔹 Today’s problem focused on simulating row and column increment operations on a matrix. 🔹 I initialized an m × n matrix with all zeros. 🔹 For each index [ri, ci], I incremented: • All elements in row ri • All elements in column ci 🔹 After applying all operations, I traversed the matrix to count how many cells contain odd values. Concepts Used: 🔹 Matrix Simulation 🔹 Nested Loops 🔹 Conditional Counting 🔹 Basic Array Manipulation Key Insight: 🔹 Direct simulation works efficiently due to small constraints. 🔹 Each operation affects an entire row and column, so tracking increments carefully is key. Complexity: 🔹 Time: O(m × n + k × (m + n)) 🔹 Space: O(m × n) #LeetCode #Algorithms #DataStructures #CodingInterview #100DaysOfCode #Python #ProblemSolving #LearningInPublic #TechCareers

I just published a deep dive into how AI agents actually work. The "agent loop" behind Claude Code, Cursor, and every coding assistant—built from scratch. 🎥 Full video: https://lnkd.in/dms7uin5 💻 Code + notebook: https://lnkd.in/dCRFp8iC We go from the official SDK (easy) to building the loop manually (educational). Key insight: The model is the agent. The code is just the harness. #AIEngineering #ClaudeCode #LLM #Python #MachineLearning #SoftwareEngineering

🗓 7 April 2026 LeetCode Problem #128 – Longest Consecutive Sequence Solved the problem of finding the longest consecutive sequence in an unsorted array. Key insight: use a set for O(1) lookups and only start counting sequences from numbers that are the beginning of a sequence. Takeaways: - Using the right data structure reduces time complexity from O(n²) to O(n). - Avoid redundant work while scanning arrays. - Handle edge cases like empty or single-element arrays efficiently. This problem reinforces how a smart approach beats brute force every time! #LeetCode #Algorithms #Python #DataStructures #ProblemSolving #Coding #TechLearning

✅ Day 95 of 100 Days LeetCode Challenge Problem: 🔹 #869 – Reordered Power of 2 🔗 https://lnkd.in/gkNXaSFM Learning Journey: 🔹 Today’s problem focused on checking whether the digits of a number can be rearranged to form a power of 2. 🔹 I created a helper function to extract and store the digits of a number. 🔹 Then I sorted the digits of the input number for comparison. 🔹 Next, I generated powers of 2 iteratively and compared their sorted digit lists with the input. 🔹 If any match was found, I returned True. Otherwise, continued until the digit length exceeded the input. Concepts Used: 🔹 Digit Extraction 🔹 Sorting 🔹 Simulation of Powers of 2 🔹 Brute Force Optimization Key Insight: 🔹 Instead of generating permutations (which is expensive), sorting digits allows quick comparison. 🔹 Any valid rearrangement must have the same digit frequency as some power of 2. Complexity: 🔹 Time: O(log n * d log d) 🔹 Space: O(d) #LeetCode #Algorithms #DataStructures #CodingInterview #100DaysOfCode #Python #ProblemSolving #LearningInPublic #TechCareers

🚀 Day 42/100 – LeetCode Challenge Solved 206. Reverse Linked List today! 🔍 Problem Summary: Given the head of a singly linked list, reverse the list and return the new head. 💡 Approach: Implemented an iterative solution using three pointers (prev, curr, next) to reverse the links efficiently in-place. Also explored the recursive approach to strengthen understanding of linked list manipulation. ⚡ Complexity: • Time Complexity: O(n) • Space Complexity: O(1) (Iterative) 📌 Key Takeaways: Importance of pointer manipulation Handling edge cases like empty list Difference between iterative vs recursive approaches Consistency is key — one step closer to mastering Data Structures & Algorithms! 💪 #LeetCode #100DaysOfCode #DataStructures #Algorithms #CodingJourney #Python #ProblemSolving #LinkedList

✅ Day 97 of 100 Days LeetCode Challenge Problem: 🔹 #1281 – Subtract the Product and Sum of Digits of an Integer 🔗 https://lnkd.in/gxTAZc6U Learning Journey: 🔹 Today’s problem involved extracting digits of a number and performing two operations simultaneously. 🔹 I initialized two variables: one for product (pr) and one for sum (sm). 🔹 Using a while loop, I extracted each digit using n % 10. 🔹 Updated the product by multiplying the digit and updated the sum by adding it. 🔹 Reduced the number using integer division (n //= 10) after each step. 🔹 Finally returned the difference between product and sum. Concepts Used: 🔹 Digit Extraction 🔹 While Loop 🔹 Arithmetic Operations 🔹 Number Manipulation Key Insight: 🔹 Both product and sum can be computed in a single traversal of digits. 🔹 Efficient use of modulus and division avoids converting the number to a string. Complexity: 🔹 Time: O(d) 🔹 Space: O(1) #LeetCode #Algorithms #DataStructures #CodingInterview #100DaysOfCode #Python #ProblemSolving #LearningInPublic #TechCareers

🚀 Stop iterating through rows like it’s 2010. In a recent pipeline, we were processing 5 million records to calculate a rolling score. Using a standard loop took forever and pegged the CPU at 100%. Before optimisation: for i in range(len(df)): df.at[i, 'score'] = df.at[i, 'val'] * 1.05 if df.at[i, 'flag'] else df.at[i, 'val'] After optimisation: import numpy as np df['score'] = np.where(df['flag'], df['val'] * 1.05, df['val']) Performance gain: 85x faster execution. Vectorisation isn’t just a "nice to have"—it’s the difference between a pipeline that crashes at 2 AM and one that finishes in seconds. By letting NumPy handle the heavy lifting in C, we eliminated the Python overhead entirely. If you're still using `.iterrows()` or manual loops for column transformations, it’s time to refactor. The performance delta on large datasets is simply too massive to ignore. What is the biggest "bottleneck" function you’ve refactored recently that gave you a massive speedup? #DataEngineering #Python #PerformanceTuning #Vectorization #DataScience

✅ Day 89 of 100 Days LeetCode Challenge Problem: 🔹 #1480 – Running Sum of 1D Array 🔗 https://lnkd.in/gSTZrxF7 Learning Journey: 🔹 Today’s problem focused on computing the running (prefix) sum of an array. 🔹 Instead of using an extra array, I optimized the solution by modifying the input array in-place. 🔹 Starting from index 1, I updated each element as: • nums[i] += nums[i-1] 🔹 This way, each index stores the cumulative sum up to that point. 🔹 Finally, returned the modified array. Concepts Used: 🔹 Prefix Sum 🔹 In-place Computation 🔹 Array Traversal Key Insight: 🔹 The previous element already stores the prefix sum, so we can reuse it directly. 🔹 Eliminates the need for extra space while maintaining linear time. Complexity: 🔹 Time: O(n) 🔹 Space: O(1) #LeetCode #Algorithms #DataStructures #CodingInterview #100DaysOfCode #Python #ProblemSolving #LearningInPublic #TechCareers

✅ Day 87 of 100 Days LeetCode Challenge Problem: 🔹 #2840 – Check if Strings Can be Made Equal With Operations II 🔗 https://lnkd.in/gY73RBb5 Learning Journey: 🔹 Today’s problem extended the previous one, allowing swaps between indices where the difference is even. 🔹 I observed that this again partitions the string into two independent groups: • Even indices (0, 2, 4, …) • Odd indices (1, 3, 5, …) 🔹 I extracted characters from even and odd positions separately for both strings. 🔹 Then, I sorted these groups and compared them between s1 and s2. 🔹 If both even-index groups and odd-index groups match, the strings can be made equal. Concepts Used: 🔹 String Manipulation 🔹 Index Grouping (Parity-based) 🔹 Sorting 🔹 Greedy Observation Key Insight: 🔹 Since swaps are allowed only between indices with even distance, characters can only move within their parity group. 🔹 Therefore, the problem reduces to checking if both parity groups have identical character distributions. Complexity: 🔹 Time: O(n log n) 🔹 Space: O(n) #LeetCode #Algorithms #DataStructures #CodingInterview #100DaysOfCode #SoftwareEngineering #Python #ProblemSolving #LearningInPublic #TechCareers