Day 63: LeetCode Challenge - Minimum Binary String Changes

✅ Day 70 of 100 Days LeetCode Challenge Problem: 🔹 #1051 – Height Checker 🔗 https://lnkd.in/g7bmj62W Learning Journey: 🔹 Today’s problem required identifying how many students are not standing in the correct order according to their heights. 🔹 I first created a sorted version of the heights array to represent the expected order. 🔹 Then I compared each element of the original list with the corresponding element in the sorted list. 🔹 Every mismatch indicates a student standing in the wrong position, so I incremented a counter for each difference. Concepts Used: 🔹 Sorting 🔹 Array Comparison 🔹 Iteration Key Insight: 🔹 Instead of rearranging elements, simply comparing the original array with its sorted version reveals how many indices differ. 🔹 Each mismatch directly contributes to the final count. Complexity: 🔹 Time: O(n log n) 🔹 Space: O(n) #LeetCode #Algorithms #DataStructures #CodingInterview #100DaysOfCode #SoftwareEngineering #Python #ProblemSolving #LearningInPublic #TechCareers

✅ Day 68 of 100 Days LeetCode Challenge Problem: 🔹 #1207 – Unique Number of Occurrences 🔗 https://lnkd.in/g2vjwwft Learning Journey: 🔹 Today’s problem required checking whether the frequency of each element in an array is unique. 🔹 I first used Counter to count how many times each number appears in the array. 🔹 Then I extracted the occurrence counts using .values(). 🔹 To verify uniqueness, I compared the length of the occurrences list with the length of a set created from those values. 🔹 If both lengths match, it means all occurrence counts are unique. Concepts Used: 🔹 Hash Map / Frequency Counting 🔹 Python Counter from collections 🔹 Sets for Uniqueness Check Key Insight: 🔹 Converting values to a set removes duplicates automatically. 🔹 If the size of the set equals the number of frequency values, then all occurrence counts are distinct. Complexity: 🔹 Time: O(n) 🔹 Space: O(n) #LeetCode #Algorithms #DataStructures #CodingInterview #100DaysOfCode #SoftwareEngineering #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

🚀 #Day41 of #100DaysOfCode 📌 Problem: 80. Remove Duplicates from Sorted Array II Today’s challenge was about handling duplicates in a sorted array while keeping the array in-place. 💡 Key Idea: The array is already sorted, so duplicates appear next to each other. We need to ensure that each number appears at most twice. Extra duplicates beyond two should be removed while maintaining the original order. 🧠 Approach: 1️⃣ Traverse the array from left to right. 2️⃣ Keep track of how many times the current number appears consecutively. 3️⃣ Allow insertion only if the occurrence count is ≤ 2. 4️⃣ Maintain an index pointer to place valid elements in the correct position. ⚡ Complexity: Time Complexity: O(n) Space Complexity: O(1) (in-place modification) #leetcode #Python #programming #coding #softwaredevelopment #100daysofcode

Day 44 of #GeekStreak60: Math Makes Algorithms Beautiful! 🧮💻 Tackled the "Partitions with Given Difference" problem on @GeeksforGeeks today. Key Learning: Sometimes the best way to solve a complex coding problem is to not code at all, just use algebra! The problem asked to find two subsets where S1 - S2 = diff. Since we also know that S1 + S2 = total_sum, adding the equations together reveals that S1 = (total_sum + diff) / 2. Just like that, a complex two-subset balancing problem collapsed into a standard 0/1 Knapsack "Subset Sum" problem! I implemented a space-optimized 1D Dynamic Programming array to count the subset combinations, achieving the solution in pure O(n x sum) time. Reducing unfamiliar problems down to known architectural patterns is the ultimate problem-solving hack. 🚀 #geekstreak60 #npci #coding #Algorithms #Python #DataStructures #DynamicProgramming #Mathematics #ProblemSolving

Just solved “Longer Contiguous Segments of Ones than Zeros” on LeetCode with 0 ms runtime ⚡ Instead of storing segments or using extra space, I approached it with a single pass linear scan. 💡 My approach: Maintain two counters: count_1 → current streak of 1s count_0 → current streak of 0s Maintain two variables: maximum_1 → longest contiguous 1s maximum_0 → longest contiguous 0s While iterating through the string: If the character is '1', increase count_1 and reset count_0 If the character is '0', increase count_0 and reset count_1 Continuously update the maximum streaks Finally check if max(1s) > max(0s) ✨ Why this works well Only one traversal O(n) time complexity O(1) space complexity Clean and simple logic Always fascinating how simple state tracking can solve problems efficiently. Back to solving more problems and sharpening problem-solving skills! 🔥 #leetcode #coding #datastructures #algorithms #programming #python #codingpractice #problemSolving #softwareengineering #techlearning #computerscience #developers #100daysofcode #codingjourney #womenintech 🚀

✅ Day 81 of 100 Days LeetCode Challenge Problem: 🔹 #1897 – Redistribute Characters to Make All Strings Equal 🔗 https://lnkd.in/gZ7wZ7JE Learning Journey: 🔹 Today’s problem required checking if we can redistribute characters so that all strings become identical. 🔹 I combined all strings and used a frequency counter to count occurrences of each character. 🔹 Since we can freely move characters between strings, the only requirement is that each character count must be divisible by the number of strings. 🔹 If any character fails this condition, it’s impossible to evenly distribute it. Concepts Used: 🔹 Hash Map / Frequency Counting (Counter) 🔹 String Concatenation 🔹 Divisibility Check Key Insight: 🔹 The exact arrangement doesn’t matter—only the total frequency distribution matters. 🔹 If every character can be equally divided among all strings, a valid configuration always exists. Complexity: 🔹 Time: O(n * k) (n = number of strings, k = average length) 🔹 Space: O(1) (bounded by alphabet size) #LeetCode #Algorithms #DataStructures #CodingInterview #100DaysOfCode #SoftwareEngineering #Python #ProblemSolving #LearningInPublic #TechCareers

🚀 Day 45 of #100DaysOfCode 📌 Problem: Rotate Array (LeetCode 189) 🔹 Problem Statement: Given an integer array nums, rotate the array to the right by k steps, where k is non-negative. 🔹 Approach: Instead of rotating the array one step at a time, we use the Reverse Technique. Steps: 1️⃣ First calculate k % n to handle large rotations. 2️⃣ Reverse the first part of the array (0 → n-k-1). 3️⃣ Reverse the second part (n-k → n-1). 4️⃣ Finally reverse the entire array. This gives the rotated array efficiently. 🔹 Time Complexity: ⏱️ O(n) 🔹 Space Complexity: 📦 O(1) (In-place rotation) 💡 Key Learning: Using array reversal is a very efficient way to rotate arrays without extra space. #DSA #LeetCode #Python #CodingChallenge #Programming

✅ Day 72 of 100 Days LeetCode Challenge Problem: 🔹 #3868 – Minimum Cost to Equalize Arrays Using Swaps 🔗 https://lnkd.in/gwbcmecy Learning Journey: 🔹 Today’s problem involved making two arrays identical with the minimum number of cross-array swaps. 🔹 Swapping within the same array is free, but swapping elements between arrays costs 1 operation. 🔹 I used Counter to count the frequency of elements in both arrays. 🔹 Then I combined the counters to check the total occurrences of each element. 🔹 If any element has an odd total frequency, it’s impossible to distribute it equally between both arrays. 🔹 Otherwise, I calculated the difference in counts between the two arrays to determine how many elements must be swapped. Concepts Used: 🔹 Frequency Counting (Counter) 🔹 Hash Maps 🔹 Greedy Counting Logic 🔹 Swap Balancing Key Insight: 🔹 For the arrays to become identical, every element must appear an even number of times across both arrays. 🔹 The imbalance of each element indicates how many swaps are required, and dividing appropriately accounts for pairwise swaps. Complexity: 🔹 Time: O(n) 🔹 Space: O(n) #LeetCode #Algorithms #DataStructures #CodingInterview #100DaysOfCode #SoftwareEngineering #Python #ProblemSolving #LearningInPublic #TechCareers

🚀 𝐃𝐚𝐲 20/60 – 60-𝐃𝐚𝐲 𝐏𝐲𝐭𝐡𝐨𝐧 𝐂𝐡𝐚𝐥𝐥𝐞𝐧𝐠𝐞 🦾 Today's topic is "𝐬𝐭𝐚𝐧𝐝𝐚𝐫𝐝 𝐦𝐨𝐝𝐮𝐥𝐞𝐬" Using standard modules in Python 𝐦𝐚𝐭𝐡, 𝐫𝐚𝐧𝐝𝐨𝐦, and 𝐩𝐥𝐚𝐭𝐟𝐨𝐫𝐦  lets you perform common, portable tasks without reinventing the wheel. The math module provides precise mathematical functions like 𝒔𝒒𝒓𝒕 and 𝒔𝒊𝒏, the random module offers simple randomness utilities such as randint and choice, and the platform module helps you inspect the interpreter and OS details to write portable code. 𝐄𝐱𝐚𝐦𝐩𝐥𝐞: 𝘪𝘮𝘱𝘰𝘳𝘵 𝘮𝘢𝘵𝘩, 𝘳𝘢𝘯𝘥𝘰𝘮, 𝘱𝘭𝘢𝘵𝘧𝘰𝘳𝘮 # math 𝘱𝘳𝘪𝘯𝘵("𝘗𝘪:", 𝘮𝘢𝘵𝘩.𝘱𝘪) 𝘱𝘳𝘪𝘯𝘵("𝘚𝘲𝘳𝘵(16):", 𝘮𝘢𝘵𝘩.𝘴𝘲𝘳𝘵(16)) # random 𝘱𝘳𝘪𝘯𝘵("𝘙𝘢𝘯𝘥𝘰𝘮 𝘪𝘯𝘵𝘦𝘨𝘦𝘳 𝘣𝘦𝘵𝘸𝘦𝘦𝘯 1 𝘢𝘯𝘥 10:", 𝘳𝘢𝘯𝘥𝘰𝘮.𝘳𝘢𝘯𝘥𝘪𝘯𝘵(1, 10)) # platform 𝘱𝘳𝘪𝘯𝘵("𝘗𝘺𝘵𝘩𝘰𝘯 𝘷𝘦𝘳𝘴𝘪𝘰𝘯:", 𝘱𝘭𝘢𝘵𝘧𝘰𝘳𝘮.𝘱𝘺𝘵𝘩𝘰𝘯_𝘷𝘦𝘳𝘴𝘪𝘰𝘯()) 𝘱𝘳𝘪𝘯𝘵("𝘖𝘚:", 𝘱𝘭𝘢𝘵𝘧𝘰𝘳𝘮.𝘴𝘺𝘴𝘵𝘦𝘮()) Understanding these operators made me realize how programs make decisions and perform actions based on logic. They may look like simple symbols, but they are essential for writing meaningful code. Step by step, building stronger logic. #learning #python #consistency #challenge #60days #coding #programming #modules