Go to http://katrina.csie.ntu.edu.tw/judgegirl/ and login with your account(student ID) and password.
Click the hyperlink "submit" corresponding to the problem you want to solve.
Click "submit" again.
Now you can see the result...
Zero point!! What's up?? Click "detail" to see what happened.
Oh, I forgot to upload my code to the SVN server...
Go to http://tortoisesvn.net/downloads.html, download and install it.
Create a folder, enter it and right click to call the popup menu, click "SVN Checkout".
Fill "svn://katrina.csie.ntu.edu.tw/<YOUR ID>/" in the first textbox.
Fill in your username and password (same to the one you use in JudgeGirl).
Use "Save authentication" to avoid inputing password again.
Create a folder named "hw<HOMEWORK NUMBER>".
Save your code named "a.c" inside.
Click "SVN Commit" on the popup menu.
You may need to check the checkbox for new created files.
Submit in JudgeGirl again, now you can see the result.
Don't forget to upload the report, named "report.pdf", in the same location of the source code before the deadline.
File names are CASE SENSITIVE.
More about SVN: http://www.csie.ntu.edu.tw/~hsinmu/courses/lib/exe/fetch.php?media=dsa_12spring:svn_introduction.pdf