Re:GitHub repository for Sedgewick's Algorithms is taken down
by gravypod on Saturday May 01, 2021 @08:14PM
(#27011170)
It looks like the original code is located here: https://algs4.cs.princeton.edu/code/
Found this in the link you provided. As you can see from the code there is a GPL license footer on each file.
Interestingly, the README includes an e-mail exchange with Kevin, who noted the code is GPL