iCoder vs Quarry

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.

Data interview practice that runs entirely on your device. Write real SQL and Python (pandas), get graded instantly, and see exactly why. NEW IN 1.1 • Designed for iPhone Duo: question and editor side by side when open, a focused layout when closed, and it adapts as you fold. • A new native design for iPhone and iPad, in light and dark mode. • 60 new problems: a staff-level data engineering set (gaps and islands, sessionisation, slowly changing dimensions, funnels, retention) and company-style SQL sets. • Clearer results: instant correct / not quite feedback, expected vs. actual tables, and the query plan for your SQL. WHAT'S INSIDE • 168 problems across three tracks: 61 SQL, 22 pandas and 85 Python (algorithms and data structures). • Real execution, real grading. Your output is checked against the expected result, with no self-marking. • Company-style practice. Filter problems written in the style of the company you're interviewing at. • Hints and full solutions when you're stuck. • Difficulty levels from Easy to Hard, grouped by topic. • A free-form Playground for scratch SQL and Python. PRIVATE BY DESIGN No accounts. No analytics. No ads. No tracking. Quarry collects nothing and works fully offline. Built by a working data engineer, for analysts, data engineers, data scientists and software engineers who want a quiet, fast place to actually practice.