Computer Science interviews are a different breed from other interviews and, as such, require specialized skills and techniques. Cracking the Technical Interview will teach you how to prepare for technical interviews, what top companies like Google and Microsoft really look for, and how to tackle the toughest programming and algorithm problems. This talk will include stories from the speaker's extensive interviewing experience as well as a live "demo" of how to tackle a technical problem.

1. Cracking the Technical Interview Cracking the Technical Interview Gayle Laakmann Founder / CEO, CareerCup.com

2. My Background UPenn BSE / MSE ‘05 in CS Ex-Engineer at Google, Microsoft and Apple + Offers from Amazon, IBM and others 3 Years on Google Hiring Committee Interviewed 120+ candidates Previously taught 2 courses at UW (Now MBA Student at Wharton / UPenn)

3. CareerCup Founded 2005 Largest source for technical interview questions (3000+ FREE questions) Services: Book (E-Book and Paper) Video Mock interviews

5. How are interviews structured? How are you evaluated? Process

6. Technical Interview Process Initial Screen (Phone / Campus) 4 - 5 on site interviews 10 min General 40 min Technical 10 min Closing

7. What do companies look for? Are you smart? Algorithmic skills Can you code? OOO, Cleanness, bug free (sort of), etc What are you like? Communication, friendliness, etc What have you done? Relevant experience, passion, etc

8. What do companies look for? Applying

9. Resume Selection Project experience! Course work Open source Independent studies Master C++ or Java Skills Passion Work Ethic

10. Resume Advice: One Page. (Seriously.) 3 Sections: Education, Employment, Projects Pet Peeve: Save file with your name

11. Why do you want to work here? What was your favorite project? Interview prep – SOFT SKILLS

12. Research the company / team Prepare 10 – 15 questions: Genuine Questions How much time do you spend coding each day? Insightful QuestionsI noticed that Google uses Standard X. How do you solve problem Y? Passion Questions What are the opportunities to learn about scalability at Google? Soft Prep – The Company / Team

13. Create Preparation Grid for Projects + (maybe) Behavioral Grid Soft Prep – Yourself

14. Strengths vs. Weaknesses Mediocre answer: “it was hard because I had to learn new languages / technologies” Not just answering Q’s – show who you are! Soft Prep – Yourself

15. How do you prep for coding questions? What do you prep? Interview prep – Tech SKILLS

16. Data structures Algorithms Concepts What to study

17. How to implement When to use (pros / cons) Data Structures

18. Implementation Space vs Time Complexity Algorithms

19. Concepts Not just a concept – know how to code!

20. Don’t practice on computer!

21. What do companies look for? Interview – soft SKILLS

22. The Interview: Chit Chat - Tips Be specific – not arrogant “Yeah, I did all the hard work for the team” “I implemented the file system, which was considered one of the hardest components.” Limited details (else too hard to follow) Ask good questions!

23. ituation ction esponse The Interview: Chit Chat - Tips S structure your responses A R

24. How do you tackle hard tech questions? Interview – tech SKILLS

25. General Advice for Technical Questions Talk out loud – show us how you think! Good interviews = hard questions Don’t be nervous if you can’t solve something! You’re not done until they say you’re done.

26. The Coding Interview: 5 Steps

27. Asking Questions What are the data types? How much data? What assumptions do you need? Who is the user? NOTE: Especially important at Microsoft.

28. OMG! I have no idea how to solve this problem! Algorithm Discovery Approaches

30. What problem is this similar to?

31. Simplify / Generalize

32. What if the data was a different type?

33. Base Case & Build

34. Can you do this just for element 1? 1 and 2? …

35. Data Structure Brainstorm

37. Algorithm Discovery Approaches Simplify / Generalize A ransom note can be formed by cutting words out of a magazine to form a new sentence. How would you figure out if a ransom note (string) can be formed from a given magazine (string)?

38. Algorithm Discovery Approaches Base Case & Build Design an algorithm to print all subsets of a set.

39. Algorithm Discovery Approaches Data Structures Brainstorm Numbers are randomly generated and sorted into an (expanding) array. How would you keep track of the median?

40. Find Problems with Your Algorithm What’s the space / time complexity? What if there’s lots of data? Does your design cause other issues? If there are other issues, did you make the right trade offs?

41. Pseudo Code & Code Pseudo code first – but tell your interviewer Use data structures generously What are the right ones? Define your own = shows good style Don’t crowd your coding Start in the upper left corner of board, not bottom

42. Testing Test your code! Extreme cases Check for user error Test general cases CAREFULLY FIX MISTAKES

43. What about non-algorithm problems? System Design Design for small system, then scale. Object Oriented Design What are the major objects? How do they interact? Trace It!

44. (eg, things that wouldn’t fit in elsewhere) FINAL THOUGHTS

45. The Interview: Ending It Smile, be positive If you think you bombed, don’t worry Follow up with your recruiters (sometimes they forget)

46. The Offer It’s always negotiable Helps if you have competing offer Don’t lie – companies know what competitors offer Is it really what you want? Money, career options, etc

47. My Red Flags: People who… … wrote code and didn’t test it … found mistakes and would make random fixes … jammed things messily into an existing data structure … didn’t consider the impact of their algorithms … were scared to try

48. Take Aways – Getting Ready Get Project Experience Show project experience on resume S. A. R. (Situation Action Result) Prepare Project / Behavioral Grids

49. Technical Interview Prep Things to know (data structures, algorithms, concepts) Simple  Know Implementation Complex  Know Concepts Practice interview questions!

50. At The Interview Be nice Interviews are supposed to be hard Approaches Pattern matching Simplify / Generalize Base Case & Build Data Structure Brainstorm

51. Other Resources E-Book Video Paper Mock Interviews Slides posted at CareerCup.com/lectures 20% Discount Code: [removed from online posting – email support@careercup.com to get it] I have removed the discount code from online posting because, well, things are Google-able and the code is intended for penn students. Please email gayle@careercup.com from your UW email address to get the code.