BigO Lens

🔍 Inline Big-O Time & Space Complexity for VS Code

See your algorithm's complexity as you write it. No AI, no API keys, fully offline.

✨ Features

🏷️ Inline Complexity Annotations

See ⏱ O(n) 📦 O(1) right after your function signature — no need to run anything. BigO Lens analyzes your code using pure AST static analysis and shows results in real-time.

🎨 Color-Coded Severity

Instantly know if your solution is optimal:

• 🟢 Good — O(1), O(log n)
• 🟡 Moderate — O(n), O(n log n)
• 🟠 Warning — O(n²), O(n³)
• 🔴 Critical — O(2ⁿ), O(n!)

📐 Smart CodeLens

Clickable complexity summary above every function with:

• Time & space complexity
• Detected algorithmic pattern
• LeetCode problem link (when applicable)

🏷️ Pattern Detection

Automatically identifies which algorithm technique you're using:

• 🎯 Two Pointer
• 🪟 Sliding Window
• 🔍 Binary Search
• 🌊 BFS / 🌲 DFS
• 📊 Dynamic Programming
• ✂️ Divide & Conquer
• 💰 Greedy
• ↩️ Backtracking
• #️⃣ Hash Map
• 📚 Stack / ⛰️ Heap
• And more...

💡 Optimization Hints

When your code exceeds the complexity threshold, BigO Lens suggests specific improvements:

⚠️ O(n²) detected — nested loop over same array
💡 Consider: HashMap lookup to reduce to O(n)
💡 Consider: Sorting + two pointers for O(n log n)

🔗 LeetCode Integration

If your function name matches a LeetCode pattern (e.g., twoSum_1, containerWithMostWater_11), BigO Lens:

• Links to the problem page
• Shows the optimal complexity
• Tells you if your solution matches ✅ or can be improved ⚠️

📄 Complexity Report

Generate a beautiful markdown report of all functions in your file — perfect for interview prep review.

Command: BigO Lens: Export Complexity Report

📦 Installation

From VS Code Marketplace

1. Open VS Code
2. Press Ctrl+Shift+X (or Cmd+Shift+X on macOS)
3. Search for "BigO Lens"
4. Click Install

From Command Line

code --install-extension YTTHEMIGHTY.bigo-lens

🚀 Quick Start

1. Open any .ts or .js file with algorithm functions
2. Look above your function — you'll see a CodeLens with complexity info
3. Look at the function signature line — inline hints show ⏱ O(n) 📦 O(1)
4. Hover over the function name — see detailed breakdown
5. Run the report command to export a full analysis

No configuration needed — it works out of the box!

⚙️ Configuration

All settings are optional. BigO Lens works with sensible defaults.

Example settings.json

{
  "bigoLens.complexityThreshold": "O(n log n)",
  "bigoLens.showOptimizationHints": true,
  "bigoLens.showLeetCodeLink": true
}

🧪 How It Works

BigO Lens uses pure AST (Abstract Syntax Tree) static analysis — no AI, no API calls, no network requests. Everything runs locally in your editor.

Detection Method

Source Code → TypeScript Compiler API → AST Walk → Pattern Matching → Big-O Result

The analyzer detects:

🗣️ Commands

🌐 Supported Languages

• ✅ TypeScript (.ts)
• ✅ JavaScript (.js)
• ✅ TypeScript React (.tsx)
• ✅ JavaScript React (.jsx)

🗺️ Roadmap

• [ ] Complexity comparison mode (multiple solutions side-by-side)
• [ ] Python support
• [ ] Java / C++ support
• [ ] Workspace-wide complexity dashboard
• [ ] Custom pattern plugins

🤝 Contributing

Contributions are welcome! See CONTRIBUTING.md for guidelines.

📝 Changelog

See CHANGELOG.md for the full release history.

📄 License

MIT © Yashvardhan Thanvi