LeetCode Patterns & Solutions

   

A progression-based guide to mastering algorithm patterns through LeetCode solutions.

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Pattern Progression

📚 View Full Learning Roadmap →

┌─────────────────────────────────────────────────────────────┐
│                    LEARNING PATH                            │
├─────────────────────────────────────────────────────────────┤
│                                                             │
│  TIER 1: Hash Map → Two Pointers → Binary Search            │
│                                                             │
│  TIER 2: Sliding Window → Stack → Monotonic Stack           │
│                                                             │
│  TIER 3: Tree DFS/BFS → Backtracking                        │
│                                                             │
│  TIER 4: Graph DFS/BFS → Topological Sort → Union-Find      │
│                                                             │
│  TIER 5: 1D DP → 2D DP → Grid DP → Interval DP              │
│                                                             │
│  TIER 6: Trie → Greedy → Heap → Bit Manipulation            │
│                                                             │
└─────────────────────────────────────────────────────────────┘

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Pattern Index

#	Pattern	Description	Detailed Guide
1	Binary Search 🔍	Eliminate half each iteration	Guide
2	Two Pointers 👆	Reduce O(n²) to O(n)	Guide
3	Sliding Window 🪟	Incremental window updates	Guide
4	Linked List 🔗	Pointer manipulation	Guide
5	Monotonic Stack 📚	Next greater/smaller element	Guide
6	Graph (DFS/BFS) 🌳	Tree/graph traversal	Guide
7	Dynamic Programming 📊	Overlapping subproblems	Guide
8	Backtracking 🔄	Explore all possibilities	Guide
9	Union-Find 🔗	Disjoint set connectivity	Guide
10	Trie 🌲	Prefix tree for strings	Guide
11	Heap 🏔️	Priority queue / top-k	Guide
12	Greedy 💡	Local optimal → global	Guide
13	Bit Manipulation 🔢	Binary operations	Guide

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Quick Reference

Pattern	Template Snippet
Binary Search	while left <= right: mid = (left+right)//2
Two Pointers	while left < right: # compare and move
Sliding Window	for right: expand; while invalid: shrink
Linked List	dummy = Node(0); dummy.next = head
Stack	if open: push; if close: pop and match
DFS	mark visited; for neighbors: recurse
DP	dp[i] = f(dp[i-1], ...)
Backtracking	choose; explore; unchoose

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Progress: 166 / 3056 files ✅

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Repository Structure

• solutions/ - Comprehensive LeetCode solutions in Python.
• patterns/ - Detailed algorithm pattern guides and mind maps.
• PROGRESS.md - Tracked history of processed problems.

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About

Solving Leetcode Solutions as I go. Each enhanced solution includes an INTUITION section explaining the technical "WHY" behind the logic.

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Commands Reference

Command	What it does
Continue	Process next batch of files
Resume from progress tracker	Pick up where we left off
Create mind map: [Name]	Create new company/topic mind map
git push	Upload progress to GitHub