Solved Mirror Pairs Problem with Hashmap Approach

Day 250 of #365DaysOfCode Solved Intervals Between Identical Elements using a hashmap with prefix sum optimization. Grouped indices of identical values and computed distances by leveraging prefix sums to avoid redundant pairwise calculations. This reduces the complexity from quadratic to linear over grouped indices. The approach efficiently calculates contributions from both left and right sides for each index. Continuing to strengthen optimization techniques using prefix sums and grouping strategies. #365DaysOfCode #Day250 #DSA #LeetCode #Python #Algorithms #PrefixSum #HashMap #ProblemSolving #Consistency

🗂️ HashMap pattern: the fastest way to improve a solution 💡 If you see 'find pair', 'count', or 'seen before' — think HashMap. Why this matters: - Turn nested loops into O(n) with a HashMap — and explain it cleanly. This topic appears repeatedly in interviews and real projects, so depth matters. 📌 If you want, I'll post a 'HashMap patterns' list with example problems. #dsa #algorithms #interviewprep #python #coding

Day 243 of #365DaysOfCode Solved Minimum Distance Between Three Equal Elements I using a hashmap-based indexing approach. Grouped indices of identical elements and evaluated triplets by scanning index lists to compute the minimum distance. This approach efficiently reduces redundant comparisons by leveraging value-based grouping. The solution runs in O(n) time with additional space for index storage. Continuing to refine problem solving through pattern recognition and efficient data organization. #365DaysOfCode #Day243 #DSA #LeetCode #Python #Algorithms #HashMap #ProblemSolving #Consistency

Group Anagrams: Frequency Signature Beats Sorting for Keying Sorting each string as key costs O(k log k) per string. Character frequency array is O(k) and creates same signature for anagrams. Fixed 26-element array converted to tuple serves as hashable HashMap key — cleaner, faster grouping. Frequency as Key: Character counts uniquely identify anagram groups. Tuple conversion enables using array as dict key (lists aren't hashable). This pattern applies to document clustering, duplicate detection. Time: O(n × k) vs O(n × k log k) with sorting | Space: O(n × k) #FrequencySignature #HashMap #Anagrams #KeyOptimization #Python #AlgorithmDesign #SoftwareEngineering

💡 Solved Group Anagrams today! 🧠 Key idea: Instead of comparing strings, I used a frequency array (size 26) to create a unique key for each word. ⚠️ Catch in constraints: All characters are lowercase English letters, which allows us to use a fixed-size array of 26 for efficient hashing. 🚀 Result: Achieved O(n · k) time complexity. Great example of converting a comparison problem into a hashing problem! #LeetCode #DSA #Algorithms #Python #CodingInterview

✅ Day 28 of #DSAPrep > Problem: Rearrange Array Elements by Sign > Platform: LeetCode > Concept: Array / Two Pointers Solved this problem using a two-pointer approach to place positive and negative numbers alternately in a new array. > Key Idea: Create a result array of same size Use one pointer for positive index (0,2,4...) Use another pointer for negative index (1,3,5...) Traverse input array and place elements accordingly > Time Complexity: O(n) > Space Complexity: O(n) #DSAPrep #Algorithms #Python #Arrays #TwoPointers #ProblemSolving #CodingJourney

✅ Day 26 of #DSAPrep > Problem: Merge Sorted Array > Platform: LeetCode > Concept: Two Pointers / Merge Technique Solved this problem by merging two sorted arrays using two pointers and storing the result in sorted order. > Key Idea: Use one pointer for each array Compare current elements Insert smaller value into result Add remaining elements at the end > Time Complexity: O(m + n) > Space Complexity: O(m + n) #DSAPrep #Algorithms #Python #TwoPointers #Arrays #ProblemSolving #CodingJourney

Search Rotated Sorted Array: Binary Search with Sorted Half Detection Rotation breaks global order but one half is always properly sorted. Determine which half is sorted by comparing mid with endpoints. If target falls within sorted half's range, search there; otherwise search rotated half. Preserves O(log n). Partial Invariant: When global invariant breaks, find preserved local properties. Here, one half always maintains sorting despite rotation. Time: O(log n) | Space: O(1) #BinarySearch #RotatedArray #PartialInvariant #SearchOptimization #Python #AlgorithmDesign #SoftwareEngineering

Day 37 / #120DaysOfCode – LeetCode Challenge ✅ Problem Solved: • Search a 2D Matrix 💻 Language: Python 📚 Key Learnings: • Applied Binary Search on a 2D matrix • Learned how to treat matrix as a flattened sorted array • Practiced converting 1D index → 2D index (row, col) • Improved understanding of search space reduction • Strengthened logarithmic time complexity (O(log n)) thinking Better logic → Faster execution 🚀 🔗 LeetCode Profile: https://lnkd.in/gbeMKcv5 #LeetCode #Python #DSA #BinarySearch #Algorithms #CodingJourney #Consistency #120DaysOfCode

Search Rotated Sorted Array: Binary Search with Sorted Half Detection Rotation disrupts global order but one half stays sorted always. Determine which half is sorted by comparing mid with endpoints. If target falls within sorted half's range, search there; otherwise search rotated half. Preserves O(log n). Partial Invariant: When global invariant breaks, find preserved local properties. One half maintains sorting despite rotation — exploit this for logarithmic search. Time: O(log n) | Space: O(1) #BinarySearch #RotatedArray #PartialInvariant #SearchOptimization #Python #AlgorithmDesign #SoftwareEngineering