"Understand the problem. Respect the constraints. Write it clean."

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About This Repo

Personal archive of LeetCode solutions — synced via LeetSync, written for clarity over cleverness.

Each solution prioritizes:

• Readable logic over micro-optimizations
• Sound complexity tradeoffs (always stated)
• Pattern-driven thinking, not brute force

Primary Language: Python | Secondary: JavaScript | DB: SQL

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LeetCode Stats

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Approach

Principle	Practice
Understand first	Map constraints and edge cases before writing a single line
Complexity first	Always define O(n) time/space before implementation
Pattern recognition	Solutions grouped by technique, not problem number
Clean code	No magic numbers. Meaningful names. Zero ambiguity.
Security mindset	Inputs treated as untrusted — always validate, never assume

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Topics Covered

leetcode-solutions/
├── Arrays & Hashing
├── Two Pointers / Sliding Window
├── Binary Search
├── Linked Lists
├── Trees & BST
├── Graphs (BFS / DFS / Dijkstra)
├── Dynamic Programming
├── Backtracking
├── Math & Bit Manipulation
├── Stack & Queue
└── SQL / Database Problems

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Difficulty Breakdown

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Featured Solutions

#	Problem	Difficulty	Topic	Language
51	N-Queens	Hard	Backtracking	Python
76	Minimum Window Substring	Hard	Sliding Window	Python
84	Largest Rectangle in Histogram	Hard	Stack	Python
303	Range Sum Query - Immutable	Easy	Prefix Sum	Python
744	Network Delay Time	Medium	Graphs / Dijkstra	Python
803	Cheapest Flights within K Stops	Medium	Graphs / Bellman-Ford	Python
1456	Find the City with Smallest Neighbors	Medium	Graphs / Floyd-Warshall	Python

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SQL Coverage

Heavy coverage on LeetCode SQL problems — JOIN strategies, window functions, subqueries, aggregations.

-- Sample pattern: Window Function approach
SELECT name,
 RANK() OVER (PARTITION BY department ORDER BY salary DESC) AS rnk
FROM employees;

Topics: GROUP BY · HAVING · JOIN types · CTE · CASE WHEN · Window Functions · Subqueries

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Tech Stack

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About the Author

Au — AI/ML Engineer · Computer Vision · Secure Systems · Philippines

Building with a focus on structure, scalability, and security.

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This repo is a working document, not a showcase. Expect ongoing commits.