You have to be very careful about spaces and returns on some of them as well. Fortunately they tend to have short and precise output specifications. I do wish

You have to be very careful about spaces and returns on some of them as well. Fortunately they tend to have short and precise output specifications. I do wish their grading script could give a little more indication of what failed, as I'm not sure it will even tell you the difference between a build error and a test failure. If it does, great. I struggled with that a year ago when I first worked on them.