Lichen: Big-O Algorithms

Algorithm complexity reference

Only for iPhone

Free · Designed for iPhone. Not verified for macOS.

iPhone

Big-O at a glance. Catalog, chart, and quiz for every classic algorithm — fully offline. Lichen is a focused, offline reference for classical algorithms and their Big-O complexity. Built for students, interview candidates, and working engineers who want fast answers without noise. A clean catalog, a side-by-side growth chart, and a quick quiz mode — all on a single dark stage. No clutter, no popups, no upsells. KEY FEATURES • Catalog of 30+ algorithms across Sort, Search, Graph, Tree, String, Dynamic Programming, Divide & Conquer, Greedy, Hashing, and Heap • Best, average, worst, and space complexities for every algorithm • Live growth-rate chart comparing O(1), O(log n), O(n), O(n log n), O(n²), O(2ⁿ), and O(n!) • Pseudocode snippets and real-world use cases on every detail page • Filter by category and by complexity class with single-tap chips • Bookmark algorithms you want to revisit • Big-O Quiz mode for spaced practice before interviews DESIGNED FOR INTERVIEW PREP Whether you are warming up for a coding round, picking the right data structure for a hot loop, or refreshing concepts before a system design call, Lichen stays out of the way and surfaces the answer in two taps. PRIVACY No tracking. No accounts. Your bookmarks live on your device.

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The developer, Linh Phan Nhat Khanh, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

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    Information

    Seller
    • Linh Phan Nhat Khanh
    Size
    • 545.8 KB
    Category
    • Reference
    Compatibility
    Requires iOS 17.0 or later.
    • iPhone
      Requires iOS 17.0 or later.
    • Mac
      Requires macOS 14.0 or later and a Mac with Apple M1 chip or later.
    • Apple Vision
      Requires visionOS 1.0 or later.
    Languages
    • English
    Age Rating
    4+
    Copyright
    • © 2026 PNKL
  • Developer Website
  • Privacy Policy

    • More by Linh Phan Nhat Khanh

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