iCoder - Advanced Algorithms

Eight years. One mission: help you master algorithms without distractions.

iCoder is a LeetCode practice app trusted since day one by learners preparing for technical interviews. Version 8.0 marks our 8th anniversary with a complete SwiftUI rebuild: faster, cleaner, and ready for iOS 16 and later. Still 1000+ classic problems, still offline, still no ad popups.

WHY iCODER

- Born for interview prep: company-tagged problems mirror what top firms often ask
- Organized by difficulty, tags, and companies so you can drill weak spots
- Offline-first: the library lives on your device; browse, quiz, and widgets work without Wi-Fi
- Eight years of polish: now with a modern SwiftUI interface and rich widgets

BROWSE AND SEARCH

- Numbered list or compact grid with adjustable columns on iPhone and iPad
- Filter by Easy, Medium, Hard, VIP, favorites, and learning status
- Optional Favorites and Recently Viewed at the top of the Problems tab
- Search by problem ID, title, content, tag, or company
- Swipe and context menus for favorites and status

CATEGORIES

- Algorithm tags from arrays to dynamic programming
- Company collections for targeted interview practice
- Smooth flow from filters to detail

PROBLEM DETAIL

- Bilingual Chinese and English descriptions
- Adjustable font size
- Unlearned, Learned, and Mastered tracking
- Toolbar favorites and solution links when online
- Share a long image for notes or study groups
- Previous and next problem navigation

DAILY QUIZ AND REVIEW

- Ten questions per day by difficulty, tag, or company
- Today score, best score, and streak
- Wrong Book with one-tap return to full problem detail
- Reshuffle for extra practice the same day

LEARNING TRACKING

- Favorites and Recently Viewed lists in Settings
- One-tap clear all recents
- Stats for favorites, learned rate, and mastered rate

WIDGETS (iOS 16 AND LATER)

- Daily Problem, Difficulty Glance, Daily Quiz, Favorites, Wrong Book, Learning Progress, Company Spotlight
- Lock Screen and StandBy compact layouts; deep-link into the app
- On iOS 17 and later: shuffle from Daily Problem and Company Spotlight Home Screen widgets without opening the app
- In-app Widget Guide with FAQ

PERSONALIZATION

- Sixteen accent colors; Light, Dark, or System
- Widget backgrounds can match your theme
- English, Simplified Chinese, Traditional Chinese, or Follow System
- List or grid layout with custom column count

SHORTCUTS

- Up to four Home Screen quick actions on long-press
- Deep links from widgets and shortcuts
- iPad and Mac keyboard shortcuts

SUPPORT

- Rate, email feedback, share the app, tip the developer
- More apps from the developer
- Optional App Store update reminder

OUR PROMISE SINCE YEAR ONE

- No ad popups inside the app
- Offline problem library
- Your time is precious; we respect it

Requires iOS 16.0 or later. Download iCoder 8.0 and celebrate eight years of practice with us.