Solving LeetCode #13 Roman to Integer in Python

Day 50/100 – #100DaysOfCode 🚀 Solved LeetCode #28 – Find the Index of the First Occurrence in a String (Python). Today I practiced string matching using a brute-force approach to find the first occurrence of a substring. Approach: 1) Traverse the main string (haystack). 2) For each index, try to match the substring (needle). 3) Compare characters one by one. 4) If all characters match, return the starting index. 5) If mismatch occurs, break and move to the next index. 6) If no match is found, return -1. Time Complexity: O(n × m) Space Complexity: O(1) Understanding basic string matching techniques step by step 💪 #LeetCode #Python #DSA #Strings #ProblemSolving #100DaysOfCode

Day 43/100 – #100DaysOfCode 🚀 Solved LeetCode #2610 – Convert an Array Into a 2D Array With Conditions (Python). Today I practiced hashmap (frequency counting) to construct a 2D array based on given conditions. Approach: 1) Create a frequency map to count occurrences of each element. 2) Initialize an empty result list. 3) While the frequency map is not empty: 4)  Create a new row. 5)  Iterate through keys and add each number once to the row. 6)  Decrease its frequency and remove it if it becomes zero. 7) Add the row to the result. 8) Return the final 2D array. Time Complexity: O(n) Space Complexity: O(n) Learning how frequency maps help in structuring data efficiently 💪 #LeetCode #Python #DSA #HashMap #Arrays #ProblemSolving #100DaysOfCode

Day 39 / #120DaysOfCode – LeetCode Challenge ✅ Problem Solved: • Integer to Roman 💻 Language: Python 📚 Key Learnings: • Learned how to map numerical values to symbolic representations • Used greedy approach for optimal conversion • Understood importance of ordered value-symbol pairing • Practiced handling special subtraction cases (IV, IX, XL, etc.) • Improved skills in writing structured and readable logic Consistency + Logic = Growth 🚀 🔗 LeetCode Profile: https://lnkd.in/gbeMKcv5 #LeetCode #Python #DSA #Algorithms #CodingJourney #Greedy #120DaysOfCode

Day 53/100 – #100DaysOfCode 🚀 Solved LeetCode #125 – Valid Palindrome (Python). Today I practiced string cleaning and validation to check whether a given string is a palindrome. Approach: 1) Traverse the string and keep only alphanumeric characters. 2) Convert all characters to lowercase. 3) Build a cleaned string. 4) Compare the string with its reverse. 5) If both are equal, return True; otherwise, return False. Time Complexity: O(n) Space Complexity: O(n) Learning how preprocessing simplifies string problems 💪 #LeetCode #Python #DSA #Strings #ProblemSolving #100DaysOfCode

Python Clarity Series – Episode 24 Topic: Late Binding in Loops (Functions) ⚠️ Advanced pitfall: Late binding in loops funcs = [] for i in range(3): funcs.append(lambda: i) for f in funcs: print(f()) Output: 2 2 2 ❗ 👉 Expected: 0 1 2 👉 Got: same value 💡 Reason: Lambda captures variable, not value. 💡 Fix: funcs.append(lambda i=i: i) 💡 Rule: Default arguments capture current value. This is a classic interview trap. #PythonAdvanced #CodingPitfalls #DeveloperLevel #python #clarity

Day 42/100 – #100DaysOfCode 🚀 Solved LeetCode #2574 – Left and Right Sum Differences (Python). Today I practiced prefix sum logic to calculate the absolute difference between left and right sums for each index. Approach: 1) Calculate the total sum of the array. 2) Initialize leftSum = 0. 3) Traverse the array. 4) For each index, compute rightSum = total - leftSum - nums[i]. 5) Calculate the absolute difference and append it to the result. 6) Update leftSum by adding nums[i]. Time Complexity: O(n) Space Complexity: O(n) Understanding prefix sum helps solve problems efficiently 💪 #LeetCode #Python #DSA #Arrays #PrefixSum #ProblemSolving #100DaysOfCode

Here's what's happening... Output: l 🐍 Did you get it right? The key here is chained indexing — name[0] gives you the string, then [1] digs into that string. Step by step: name[0] → "Ali" (first element of the tuple) "Ali"[1] → "l" (second character of the string, index starts at 0!) ✅ This is called chained indexing. Follow for more Python puzzles 🔥 #python #pythontips #learnpython #pythonprogramming #viral

Day 55/100 – #100DaysOfCode 🚀 Solved LeetCode #205 – Isomorphic Strings (Python). Today I practiced hashmap (dictionary) usage to check whether two strings follow the same pattern. Approach: 1) Create two hashmaps to store character mappings in both directions. 2) Traverse both strings together using zip(). 3) Check if the current mapping is consistent in both maps. 4) If any mismatch is found, return False. 5) Otherwise, update the mappings and continue. 6) If all mappings are valid, return True. Time Complexity: O(n) Space Complexity: O(n) Understanding how bidirectional mapping ensures consistency 💪 #LeetCode #Python #DSA #HashMap #Strings #ProblemSolving #100DaysOfCode

Beyond String Concatenation  When I started, I used to concatenate strings the old-school way. It was messy, prone to errors, and hard to read The Problem: Using + requires manual type conversion (like str(21)) and gets confusing with all the extra quotes and spaces Solution: F-strings Introduced in Python 3.6, F-strings makes your code: ✅ Readable: You see the full sentence structure ✅ Fast: They are more efficient than older methods ✅ Flexible: You can perform math or call methods directly inside { } It’s a small concept, but it’s one of the easiest ways to make code look 10x more professional. #Python #30DaysOfCode #BCA #LearningInPublic #Day21 #JECRC Day 21/30

Day 39/100 – #100DaysOfCode 🚀 Solved LeetCode #2215 – Find the Difference of Two Arrays (Python). Today I practiced set operations to efficiently find distinct elements between two arrays. Approach: 1) Convert both arrays into sets to remove duplicates. 2) Find elements present in nums1 but not in nums2 using set difference. 3) Find elements present in nums2 but not in nums1. 4) Convert both results back to lists. 5) Return the final list of differences. Time Complexity: O(n + m) Space Complexity: O(n + m) Understanding how set operations simplify comparison problems 💪 #LeetCode #Python #DSA #Sets #Arrays #ProblemSolving #100DaysOfCode