Splitting and Joining Strings with Python

🚀 Day 56 — LeetCode 451: Sort Characters by Frequency using HashMap + Sorting. 💡 Key Learnings: • Counting character frequency using dictionary • Custom sorting with key=lambda • Efficient string building using "".join() • Understanding time vs space complexity trade-offs ⏱️ Complexity: Time — O(n + k log k) Space — O(k) #Day56 #LeetCode #Python #DataStructures #DSA #CodingJourney #ProblemSolving

Solved an interesting array problem using prefix sums + hash maps 🚀 This solution efficiently finds the longest subarray based on a comparison condition (arr[i] > k) by converting the problem into a prefix sum balance and tracking first occurrences with a hashmap. ✅ O(n) time complexity ✅ Smart use of prefix sums ✅ Great example of turning a complex condition into a simple math problem Always fun when problem-solving meets optimization! 💻📊 #Python #DataStructures #Algorithms #CodingInterview #ProblemSolving #100DaysOfCode

🎥 Demo in action! Yesterday I shared screenshots of my Movie Recommendation System. Here’s a quick 50-second walkthrough of how it actually works. Select a movie → Instantly get 5 similar recommendations with posters. Built using: • Content-based filtering • CountVectorizer • Cosine similarity • Streamlit + Python Still improving it — next step: collaborative filtering. Would love your thoughts 🙌 #MachineLearning #Python #RecommendationSystem #StudentDeveloper

LeetCode | Squares of a Sorted Array 🔢 🔹 Approaches: • Two Pointers (Optimal) • Square + Sort 🔹 Time Complexity: O(n) optimal / O(n log n) sorting 🔹 Space Complexity: O(n) Daily DSA practice to improve logic and consistency 🚀 “We compare absolute values from both ends to build the sorted squares efficiently.” #LeetCode #DSA #Arrays #TwoPointers #Python #CodingJourney #LearningInPublic 

LeetCode | Find Numbers with Even Number of Digits 🔢 🔹 Approaches: • Digit counting using division • String length conversion 🔹 Time Complexity: O(n) 🔹 Space Complexity: O(1) Daily DSA practice to improve logic and consistency 🚀 “We count digits either mathematically or using string length, then check if it’s even.” #LeetCode #DSA #Arrays #Python #CodingJourney #LearningInPublic 

Day 42 ✅ | Reverse Linked List Revisited one of the most important linked list problems today. The goal is to reverse the list in-place by carefully adjusting node pointers. Key ideas used: Maintain prev and curr pointers Temporarily store the next node Reverse links step by step while traversing the list This problem is a great reminder that mastering the basics makes harder problems much easier 💪 #Python #LeetCode #LinkedList #ReverseLinkedList #ProblemSolving #Day42 #CodingJourney #DSA #Algorithms #DataStructures

LeetCode #226 – Invert Binary Tree | Python Implementation I implemented a recursive DFS approach that swaps left and right children at every node. Core Insight: Tree inversion is distributive — inverting a tree equals swapping its root's children and inverting each subtree independently. Recursion handles this naturally in O(n) time. Time: O(n) | Space: O(h) where h = tree height (recursion stack) #LeetCode #DataStructures #Python #BinaryTree #Recursion #DFS #CodingInterview #SoftwareEngineering

Day 32 of #100DaysOfCode 🚀 Today’s LeetCode lesson wasn’t about algorithms — it was about reading errors carefully. 🔍 Problem: Minimum Removals to Balance Array 💡 Approach: Sorting + Sliding Window (Two Pointers) But I hit a Runtime Error even though my logic was correct. Takeaways: Always match the exact function name expected by the platform Don’t panic on runtime errors — read the driver message carefully Logic can be perfect, but naming matters 🧠 Final solution uses: Sorting Two pointers O(n log n) time complexity Consistency > Speed. Small details > Big mistakes. On to the next problem 💪 #100DaysOfCode #LeetCode #Python #DSA #ProblemSolving #CodingJourney #LearningByDoing

🚀 𝗗𝗮𝘆 𝟯/𝟯𝟬 — 𝗗𝗦𝗔 𝗖𝗵𝗮𝗹𝗹𝗲𝗻𝗴𝗲 Consistency check ✔️ Today was about working with counting and uniqueness patterns — figuring out when a set or dictionary can save you from writing unnecessary loops (and unnecessary headaches). 🔎 𝗗𝗮𝘆 𝟯 𝗙𝗼𝗰𝘂𝘀 • Frequency/count tracking • Using sets for uniqueness checks • Solved: ✅ Majority Element ✅ Missing Number ✅ Single Number Small progress, fewer overcomplicated solutions, and only mild confusion — I’ll take that as a win On to Day 4 💪 #DSA #Python #LeetCode #LearningInPublic #Consistency #SoftwareEngineering

Still slicing DataFrames the hard way? Here are the three essentials: grab one column with df['col'], pick multiple with df[['a','b']], then filter rows by building a boolean mask like df[df['age'] >= 18]. Master these and inspecting/subsetting data becomes effortless.#pandas #python #datascience #dataanalysis