Introduction to Problem Solving Alexey Onufriev Departments of Computer Science and Physics Virginia Tech Copyright ©

The key premise: Problem solving is not an innate ability (you either have it or you don’t). It’s a skill that can be learned and honed.

Goals of This Course Make you a better problem solver in general – Understand how you operate – Recognize limitations and pitfalls – Learn general techniques that you can apply to solve problems – Learn how to form successful teams and function within a team. Improve your ability to successfully complete the CS degree Learning a specific skill (such programming) is NOT the goal

CS2104 is for you if at least some of these apply: You want to occupy upper levels of professional hierarchy You want to go to graduate school You want to be able to find a high-end job even in adverse conditions You want to learn how to function within a team You want to work for highly creative companies such as Google

CS2104 is NOT for you if you: want to be a low end, specialized programmer (perhaps a very good one at that). just want to learn specific sets of skills. are certain you are not going to grad. school are sure there will always be a job waiting for you in a specific area. Can’t stand it when class does not strictly follow a textbook. Hate any whiff of open-endedness in problems (every detail must be specified)

Salaries in the outsourcing world

Why bother?

What Motivated This Course? We designed this course in hopes of: Improving students’ ability to design Improving students’ ability to develop algorithms Improving students’ ability to plan (projects) Improving students’ performance on tests Improving students’ analytical abilities Improving students’ ability to “argue” (proving) Improving students’ ability with personal interactions

Guiding Philosphy 1.Problem solving is a skill (it can be learned). It is not an innate ability. 2.Problem solving is fundamentally about attitude and effort (the “problem-solving stance”). 3.The problem-solving stance isn’t something that you can just “turn on” when you need it for a test, etc. You have to live it – and successful people do just that.

Course Organization/Process Learn about yourself Learn problem-solving techniques Solve a wide variety of problems, so as to learn how to apply the specific heuristics (techniques. E.g. “simplify” ) Understand errors typically made by poor problem solvers. Learn to avoid. Learn how to work as part of a team

What Kinds of Problems? Problems “in the small”: Puzzles, word problems, math problems (simple math), algorithmic problems (will very require basic programming skills, but focus is NOT on programming) – Heuristics Problems “in the large”: “Real life” problems – A whole “pipe-line”. Requires a task force of 4-5 people working in sync. 1-2 in-class projects + 1 homework larger project that uses what we have learned. Interpersonal problems – Take a “problem-solving” stance – Team work

Know Yourself Whimbey Analytical Skills Inventory (WASI) Myers-Briggs Personality Type (Homework Assignment 1) (It is good to do a couple of different MB tests, results vary somewhat. Then, read the descriptions.) Soloman & Felder Index of Learning Styles Thomas-Kilmann Conflict Mode Instrument

The day-to-day: Course website:

Grades: Final ~ 240 points Project ~ 200 Homeworks ~ 200 (from about 7 ) Quizzes ~ (3-5 ) In-class ~ “Bonus Activity” ~ for 5-10 most active people Extra Credit

class performance varies significantly from year to year: year: ‘09 ‘10 total score grade # of people >90 A A- 6 5 <50 F C C B B B- 7 2 your total score = 100*(your actual total)/(your max possible without items dropped as discussed in class). NO CURVES or any other funny business.

Grade Distribution, Fall 2015

Grade distribution Spring 15

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An interview Google/Microsoft real interview questions

“Testing out” of this class Deadline for telling me you want to test out: within 1 st three weeks of classes. No exceptions. First, you take the final (similar to the real one). Same time limit, same types of logical/probability/math problems, drawn from, or similar to Google/Microsoft interviews. No programming. Example: In a country in which people only want boys, every family continues to have children until they have a boy. If they have a girl, they have another child. If they have a boy, they stop. What is the proportion of boys to girls in the country? If you get less than 90%, you must go back to class, your score is erased. If >=90%, you are allowed to proceed. As the 2 nd step, you complete the project (all 3 phases, submit just one final report + the code, same total points, same grading principles. 1.5 month to complete, can work in a group of up to 4 people, also testing out). Once you take on the project, there is no turning back, you must finish, and can’t go back to class in the middle of it. The assumption is you know the stuff well, so my input will be limited to explaining the problem setup and the submission format. Your final grade in class will be based on the project and the final scores only, according to my standard scheme.