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Weekly Contest for September 27, 2011

Join the Contest

 % cd your-pc2-directory
 % /homes/cs390cp/pc2/bin/pc2team &

Log in using your individually assigned “teamX” account and password. You can work in the current window/directory, creating a subdirectory for each problem.


Remember: If you've already solved one or more of these problems, try (1) solving again without referring to your old solution, and/or (2) using a different language (Java or C++). If you want to work on an additional problem from the book, let me know.


  • A: Find a pattern. The solution is extremely short and efficient.
  • B: Repeated divisions is fine (be sure to skip even numbers after 2 and only test as large as necessary).
  • C: Observe that, if k is even, n ^ k mod p is (n ^ (k/2) mod p) ^ 2 mod p. Generalize and handle the case for k odd.
  • D: Combine the two preludes.
contest_2011-09-27.1316975967.txt.gz · Last modified: 2011/09/25 11:39 by jtkorb