Code Puzzles [1] sounds like exactly what you're talking about for iOS, and it's a really well put together app with very clear solution write-ups. There's also

Code Puzzles [1] sounds like exactly what you're talking about for iOS, and it's a really well put together app with very clear solution write-ups. There's also Cracking the Coding Interview's app [2] which has mobile videos for purchase. On the non-mobile side, there's the classic Project Euler [3] and Puzzle Node [4]. If you search around on Quizlet, you can find flash cards for just about any CS topic, including programming interview topics [5]. There are some mobile apps for Quizlet viewing as well. [1] https://itunes.apple.com/us/app/code-puzzles/id566255734?mt=8 https://itunes.apple.com/us/app/code-puzzles/id566255734?mt=... [2] https://itunes.apple.com/us/app/cracking-coding-interview/id491856690?mt=8 https://itunes.apple.com/us/app/cracking-coding-interview/id... [3] http://projecteuler.net/problems http://projecteuler.net/problems [4] http://puzzlenode.com/ http://puzzlenode.com/ [5] http://quizlet.com/16481093/programming-interview-questions-flash-cards/ http://quizlet.com/16481093/programming-interview-questions-...