contest_2011-09-27
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Table of Contents
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.
Problems
- F: Factovisors
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.
Hints:
- 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 fork
odd. - D: Combine the two preludes.
- E: The GCD algorithm given in the text solves this problem directly.
- F:
contest_2011-09-27.1316977010.txt.gz · Last modified: 2011/09/25 11:56 by jtkorb