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Competitive Programming and Contests

• Teacher: Rossano Venturini
• CFU: 6
• Period: First semester
• Language: English
• Classroom: here. Code is d77kira
• Lectures schedule: Monday 9-11 Room C1 and Thursday 9-11 Room C1 -- (Google Meet, link on our classroom)
• Question time: After lectures or by appointment

Goals and opportunities

The goal of the course is to improve programming and problem-solving skills of the students by facing them with difficult problems and by presenting the techniques that help their reasoning in the implementation of correct and efficient solutions. The importance of these skills has been recognized by the most important software companies worldwide, which evaluate candidates in their job interviews mostly by the ability in addressing such difficult problems (e.g., see here).

A natural goal is to involve the students in the intellectual pleasure of programming and problem solving, also preparing them for the most important international online contests, such as Topcoder, Codeforces, HackerRank, CodeChef, Facebook Hacker Cup, Google Code Jam and so on, for internships in most important companies and their interviews. A desirable side-effect of the course could be to organize and prepare teams of students for online contests.

The course will provide the opportunity of

• facing with challenging algorithmic problems;
• improving problem solving and programming skills;
• getting in touch with some big companies for internships, scholarships, or thesis proposals.

Exam

See these slides. Mandatory exercises for homeworks are in bold.

Extra points for

• active participation
• serious participation to online contests, e.g., CodeForces, TopCoder, Hacker Rank, Google Code Jam, ...
• successful interview with a big company

Implementing solutions for the problems of each lecture is strongly recommended to improve your problem solving skill and to practice with Rust.

I recommend you to create a github repository to collect all your solutions and their descriptions. The repository can be either private or public. In both cases I should be able to access it. Please send me a link to your repository and keep the repository updated. I should be able to monitor your progresses.

Upcoming Exams

Type	Date	Room
Written/Lab	03/02/2022 9:00	Google Meet

Old Exams

Type	Date	Text
Written/Lab	23/01/2018 9:30	Text, TestSet, and Solution
Written/Lab	14/02/2018 9:30	Text, TestSet, and Quadratic solution
Written/Lab	12/06/2018 14:00	Text, TestSet, and Solution
Written/Lab	06/07/2018 9:30	Text and TestSet
Written/Lab	14/01/2019 14:00	Text and TestSet

How to solve a problem

• Read carefully the description of the problem.
• Make sure you understand the problem by checking the examples.
• Design a first trivial solution.
• Think about a more efficient solution. The use of some running examples usually helps a lot in finding a better solution. If your are not able to find such solution, try to find some hints by discussing with other students, by asking questions on the group, by looking at the solution in our Web page, or by searching on internet. This is perfectly fine for the first problems and for most difficult ones. In any case, make sure you really understand the solution and the properties it is exploiting!
• Write a brief description of your solution in English. Provide an analysis of its time and space complexity.
• Implement your own solution.
• Submit your implementation to the problem's site. Fix it until it passes all the tests.
• Always compare your solution and your implementation with existing ones.

Background

If you wish to refresh your mind on basic Algorithms and Data Structures, I suggest you to look at the well-known book Introduction to Algorithms, 3rd Edition by Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest, Clifford Stein.

I strongly suggest you to watch the following video lectures as soon as possible.

• Insertion Sort and Merge Sort
• Heaps and Heap Sort
• Counting Sort, Radix Sort, Lower Bounds for Sorting
• Binary Search Trees
• AVL trees
• Hashing with Chaining

References

• Introduction to Algorithms,  3rd Edition, Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest, Clifford Stein, The MIT Press, 2009 (Amazon) [CCLR]
• Algorithms, 4th Edition, Robert Sedgewick, Kevin Wayne, Addison-Wesley Professional, 2011 (Amazon) [RS]
• Algorithms, Sanjoy Dasgupta, Christos Papadimitriou, Umesh Vazirani, McGraw-Hill, 2006. (Amazon) [DPZ]
• Programming Challenges: The Programming Contest Training Manual, Steven S. Skiena, Miguel A. Revilla, Springer, 2003 (Amazon) [SR]
• Competitive Programming 4: The New Lower Bound of Programming Contests, Steven Halim, Felix Halim, (here) [HH]
• Guide to Competitive Programming: Learning and Improving Algorithms Through Contests. Second Edition, Antti Laaksonen, Springer, 2020 (here) [L]

Rust

• The Rust Programming Language
  • Videos
• The Rust Reference
• The Rust Standard Library
• Rust users forum
• Rustlings

C++

• The C++ Programming Language, 4th Edition, Bjarne Stroustrup, Addison-Wesley Professional, 2013 (Amazon)
• A Tour of C++, 2nd Edition, Bjarne Stroustrup, Addison-Wesley Professional, 2018 (Amazon)
• The C++ Standard Library: A Tutorial and Reference, 2nd Edition, Nicolai M. Josuttis, Addison-Wesley Professional, 2012 (Amazon)

Useful links

• Erik D Demaine, Srini Devadas, Nancy Ann Lynch, "MIT  Design and Analysis of Algorithms", MIT Algorithm course which includes video lectures
• Tim Roughgarden, "Algorithm specialization", Coursera
• Visualgo: visualising data structures and algorithms through animation
• Geeks for Geeks: Company interviews preparation
• Interviews common coding questions
• How to: Work at Google — Example Coding/Engineering Interview Video
• Google's Code Jam
• Topcoder
• Codeforces
• LeetCode
• HackerRank
• Geeks for Geeks
• LeetCode
• CodeChef - Data Structures and Algorithms links
• Geeks for Geeks: Top 10 Algorithms and Data Structures for Competitive Programming
• List of resources for competitive programming

Lectures

Date	Lecture	References	Problems
15/09/2022	Introduction	Slides	Leaders in array (solution), Kadane's algorithm (solution), and Missing number in array (solution)
19/09/2022	Solutions of Trapping rain water and Sliding window maximum	Rossano's notes*	Trapping rain water (solution), and Sliding window maximum (solution)
22/09/2022	Analysis and correctness of Sliding window maximum. Brief introduction to Rust.		Next greater element and Towers (solution)
29/09/2022	Searching and Sorting: Binary Search, Merge Sort, QuickSort, Counting Sort, and Radix Sort	Rossano's notes*. [CCLR] Chapters 2.3, 7, and 8. Binary search. Exponential search. Interpolation search (optional)