December 2017
 

[url]https://researchweb.watson.ibm.com/haifa/ponderthis/challenges/December2017.html[/url]

C'mon man, that is trivial...
(hint: Claude Berge)

My son think he found an answer longer than the required 27....he's just double checking it

...oops....back to the drawing board.

[url]https://researchweb.watson.ibm.com/haifa/ponderthis/solutions/December2017.html[/url]

What seems strange to me is that I only see four Romanians in that list... They used to teach graph theory in school there... :sad:
...hehe...