🧠 Python LeetCode Patterns & Cheat Sheet

This repository is a curated, interview-focused collection of reusable code templates, problem-solving patterns, and optimized Python solutions to help you prepare for coding interviews. It covers all core data structures and algorithms, from arrays to dynamic programming and graphs.

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🚀 What's Included

• ✅ Reusable Python templates for each pattern
• ✅ Categorized by topic: arrays, trees, dp, graphs, etc.
• ✅ Clean code & best practices
• ✅ Interview-ready answers
• ✅ Personal tracker.csv to log your progress

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📂 Repository Structure

Click to expand

leetcode-patterns-python/
├── arrays/
│   ├── two_sum.py
│   ├── group_anagrams.py
│   └── top_k_frequent.py
├── twopointers/
│   ├── three_sum.py
│   └── container_with_most_water.py
├── sliding_window/
│   ├── longest_substring.py
│   └── min_subarray_len.py
├── stack_queue/
│   ├── valid_parentheses.py
│   ├── daily_temperatures.py
│   └── implement_queue_using_stacks.py
├── linked_list/
│   ├── reverse_linked_list.py
│   ├── merge_two_sorted_lists.py
│   ├── detect_cycle.py
│   └── middle_node.py
├── trees/
│   ├── max_depth.py
│   ├── invert_tree.py
│   ├── level_order_traversal.py
│   └── symmetric_tree.py
├── backtracking/
│   ├── subsets.py
│   ├── permutations.py
│   └── combination_sum.py
├── dp/
│   ├── climb_stairs.py
│   ├── house_robber.py
│   ├── coin_change.py
│   └── longest_increasing_subsequence.py
├── graphs/
│   ├── num_islands.py
│   ├── clone_graph.py
│   ├── rotting_oranges.py
│   └── course_schedule.py
├── tracker.csv  # Practice log
└── README.md

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🧩 Practice Tracker (tracker.csv)

Use this to track your LeetCode journey!

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🧠 Key Topics Covered

Category	Patterns & Techniques
Arrays & Hashes	Two Sum, Group Anagrams, Top-K Frequent
Two Pointers	3Sum, Container With Most Water
Sliding Window	Longest Substring, Min Subarray Length
Stack/Queue	Valid Parentheses, Monotonic Stack, Implement Queue
Linked Lists	Reversal, Cycle Detection, Merging, Middle
Trees	DFS, BFS, Inversion, Symmetry
Backtracking	Subsets, Permutations, Combination Sum
Dynamic Prog.	Climb Stairs, House Robber, Coin Change
Graphs	DFS/BFS, Islands, Clone Graph, Topological Sort

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📌 TODOs

• Add more templates (e.g. Tries, Union-Find, Segment Trees)
• Add test cases using unittest
• Add Markdown notes for each topic

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📫 Contact

Pull requests and improvements welcome!