Solved LeetCode #2215 with Python Set Operations

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

Day 46/100 – #100DaysOfCode 🚀 Solved LeetCode #2733 – Neither Minimum nor Maximum (Python). Today I practiced sorting and simple array logic to find any element that is neither the minimum nor the maximum in the array. Approach: 1) Sort the array. 2) Check the length of the array. 3) If the size is less than or equal to 2, return -1 (no valid element exists). 4) Otherwise, return the second element as it will be neither min nor max. Time Complexity: O(n log n) Space Complexity: O(1) Understanding how sorting simplifies boundary-based problems 💪 #LeetCode #Python #DSA #Arrays #Sorting #ProblemSolving #100DaysOfCode

Day 38/100 – #100DaysOfCode 🚀 Solved LeetCode #2011 – Final Value of Variable After Performing Operations (Python). Today I practiced string handling and simple iteration to compute the final value after a series of operations. Approach: 1) Initialize a variable x = 0. 2) Traverse through each operation in the list. 3) If the operation contains "++", increment x by 1. 4) Otherwise, decrement x by 1. 5) Return the final value of x. Time Complexity: O(n) Space Complexity: O(1) Simple logic but great practice for handling strings and loops 💪 #LeetCode #Python #DSA #Strings #ProblemSolving #100DaysOfCode

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 33/100 – #100DaysOfCode 🚀 Solved LeetCode #1480 – Running Sum of 1d Array (Python). Today I practiced prefix sum logic to compute the running sum of an array. Approach: 1) Initialize an empty list to store the running sum. 2) Maintain a variable sum = 0. 3) Traverse the array and keep adding each element to sum. 4) Append the updated sum to the result list. 5) Return the final running sum array. Time Complexity: O(n) Space Complexity: O(n) Understanding prefix sums helps solve many array problems efficiently 💪 #LeetCode #Python #DSA #Arrays #PrefixSum #ProblemSolving #100DaysOfCode

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

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

Day 49/60 #geekstreak60 Solved Segregate 0s and 1s today. A simple yet useful problem that teaches the power of the two-pointer approach — solving efficiently in O(n) time and O(1) space without extra memory. Small problems like these build strong problem-solving habits step by step. 💻 #geekstreak60 #npci #DSA #Python #ProblemSolving #CodingJourney

🚀 Day 13 of My Python + DSA Journey Today’s problem focused on frequency counting 👇 ✅ Majority Element (#169) 💡 Majority Element Find the element that appears more than n/2 times 🔍 Approach: Used hashmap → counted frequency and returned element exceeding n/2 ⏱ O(n) time | O(n) space 🔥 What I learned today: • Hashmaps make counting problems simple • Frequency-based logic is very common in arrays • Early exit improves efficiency Getting faster at recognizing patterns ⚡ #Day13 #LeetCode #Python #DSA #CodingJourney #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