[Oops.] 09-apsp, exercise 4, "cycle of length zero"

[ning-y]

The error is in the first edition (as in 1st edition/09-apsp.pdf).

Chapter number or note title: 9

Page number: 321

Error description: Exercise 4 asks about cycles with length zero. You probably meant that as cycles of weight zero?

Suggested fix (if any): Cycles of weight zero.