Sketches of solution ideas
Solutions and test data (gzipped tar)

In each problem folder there is a judge's solution entitled "solution.cc". Also, there are multiple test cases, where each test has an associated x.in (the input file) and x.out (the output file, or in some cases, a hint for the checker program). For problem folders without a checker.cc file, the output of a correct solution on x.in should exactly match the contents of x.out; you can check this in Unix via diff. When there is a checker, you should compile the checker, e.g.:

g++ checker.cc -o checker

Now to check correctness of your program on a particular input, e.g. x.in, you should do the following:

$ g++ my_solution.cc -o sol
$ ./sol < x.in > x.ans
$ ./checker x.in x.ans x.out

The checker will output "OK" if your solution passed on x.in.