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Data Structures & Algorithms Articles

Hand-picked programming notes, guides, and tutorials for your placement preparation.

Monotonic Stack Explained: Next Greater Element & Largest Rectangle
Data Structures & Algorithms

Monotonic Stack Explained: Next Greater Element & Largest Rectangle

Master the Monotonic Stack pattern used in top coding interviews. Learn how to solve Next Greater Element, Largest Rectangle in Histogram, and similar problems in **O(N)** time with intuitive explanations, Python examples, visual walkthroughs, and interview-ready techniques.

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Bit Manipulation Tricks Every Developer Should Know (With Examples)
Data Structures & Algorithms

Bit Manipulation Tricks Every Developer Should Know (With Examples)

Master the most useful bit manipulation tricks used in coding interviews and competitive programming. Learn how bitwise operators work, perform fast binary operations, count set bits with Brian Kernighan’s algorithm, use bit masking, and solve common interview problems with clear explanations, practical examples, and a handy cheat sheet.

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Fenwick Tree (Binary Indexed Tree): Complete Guide with Python, Diagrams & Interview Questions
Data Structures & Algorithms

Fenwick Tree (Binary Indexed Tree): Complete Guide with Python, Diagrams & Interview Questions

Learn how the Fenwick Tree (Binary Indexed Tree) works with intuitive explanations, visual diagrams, and step-by-step examples. This complete guide covers the Least Significant Bit (LSB), point updates, prefix and range sum queries, Python implementation, complexity analysis, interview tips, and common mistakes to help you master one of the most important data structures for coding interviews and competitive programming.

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LeetCode Patterns Every Student Should Know (2026 Guide)
Data Structures & Algorithms

LeetCode Patterns Every Student Should Know (2026 Guide)

Stop solving LeetCode problems randomly. Learn the seven core coding patterns that power most interview questions at top tech companies. This guide covers Two Pointers, Sliding Window, Binary Search, BFS, DFS, Backtracking, Merge Intervals, and more, with practical examples and study strategies to help you recognize patterns instead of memorizing solutions.

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LRU Cache Explained: HashMap + Doubly Linked List (Python Guide)
Data Structures & Algorithms

LRU Cache Explained: HashMap + Doubly Linked List (Python Guide)

Learn how the LRU (Least Recently Used) Cache achieves constant-time get and put operations by combining a HashMap with a Doubly Linked List. This guide includes Python implementations, visual explanations, interview pitfalls, production-ready alternatives using OrderedDict, and real-world applications in Redis, databases, browsers, and operating systems.

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Kadane's Algorithm Explained: Maximum Subarray Sum in O(N)
Data Structures & Algorithms

Kadane's Algorithm Explained: Maximum Subarray Sum in O(N)

Master Kadane's Algorithm with an intuitive explanation, visual walkthrough, Python implementation, and interview tips. Learn how this elegant dynamic programming technique finds the maximum subarray sum in O(N) time while handling tricky edge cases like all-negative arrays.

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Prefix Sum vs Difference Array: Master Range Queries and Range Updates in DSA
Data Structures & Algorithms

Prefix Sum vs Difference Array: Master Range Queries and Range Updates in DSA

Struggling with Time Limit Exceeded (TLE) errors in array problems? Learn how Prefix Sums and Difference Arrays transform expensive O(N×Q) solutions into efficient O(N+Q) algorithms. This guide covers the intuition, formulas, Python implementations, complexity analysis, and interview tips you need to master both techniques.

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