The Stanford CS curriculum only distinguishes on the first digit: 1XX for undergrads and 2XX and above for graduate students. (Undergrads often take one or more graduate courses as they progress.)

Most taking this course are advanced 2nd year or 3rd or 4th year students who have taken the introduction to algorithms course. Most/many CS majors never take this class at all.

Ok, for a second-year course that's pretty impressive. I don't know why, I was expecting a postgrad-level course