PyGrinder vs Quarry

AI checks your Python code like a real FAANG interviewer. 50 tasks, 20-minute timer, detailed review. One purchase. No subscriptions. Practice makes perfect — when you get instant, specific feedback on every solution. PyGrinder simulates the pressure of a real coding interview: strict timer, AI evaluation, and a verdict you can trust. WHY 50 PROBLEMS MATTER: Most interview prep apps give you 10-15 tasks. You memorize them in a weekend and run out. With 50 hand-picked Python problems — Easy to Hard, across every major topic — you build real algorithmic thinking, not muscle memory. WHAT YOU GET: • AI code review — analyzes structure, complexity, and patterns (not just "correct" or "wrong") • 50 Python problems: Easy to Hard, no filler tasks • 20-minute timer — real interview pressure • Daily Challenge — one new task every day • Detailed checklist: AI answers 5 specific questions about your solution • Big O comparison: your complexity vs optimal • Side-by-side code view with reference solution • Actionable fix plan: what to change and why • Filter by difficulty and topic (Arrays, Two Pointers, DP, Stack, Graphs, Heap...) HOW IT WORKS: 1. Pick a problem or take the Daily Challenge 2. Write Python code in the built-in editor 3. Submit under the 20-minute timer 4. Get your verdict: PASS or FAIL with score (1-10) 5. See the exact line with the issue 6. Unlock full review, complexity analysis, and fix plan PERFECT FOR: • Junior Python developers preparing for technical screens • CS students applying to internships • Self-taught programmers who need structured practice • Anyone improving algorithmic thinking TOPICS: Arrays & Hashing, Two Pointers, Sliding Window, Stack, Binary Search, Linked List, Heap, Dynamic Programming, BFS & Graphs, Binary Tree, Design, Math, Bit Manipulation One purchase unlocks everything. No subscriptions. No accounts. Just code, get reviewed, improve. Download PyGrinder and walk into your interview ready.

Quarry is a focused, offline gym for data and coding interviews. 108 hand-picked problems across SQL, pandas, and Python — write real code, run it on your device, and get graded instantly. Everything runs on-device. The SQL and Python engines are built into the app, so there's no sign-up, no internet requirement, and nothing you write ever leaves your phone or iPad. Practice on a plane, on the subway, or anywhere. WHAT'S INSIDE • 108 problems across three tracks: SQL queries, pandas data wrangling, and Python algorithms & data structures. • Real execution, real grading. Your output is checked against the expected result — no self-marking. • Company tags. Filter problems by 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. • Universal app — designed for both iPhone and iPad. PRIVATE BY DESIGN No accounts. No analytics. No ads. No tracking. Quarry collects nothing and works fully offline. Whether you're prepping for a data analyst, data engineer, data scientist, or software role, Quarry gives you a quiet, fast place to actually practice.