Should I use Dijkstra's algorithm several times for each friend or just floyd-warshall?

I think so

You can use BFS.

..? good q ..
but .. !
all the edge's cost's are 1 .. so .. :-)
use BFS .. for every friend from its starting position :-)

its n*k :-)

.. but i got WA 14 :-( ...


~~~~~~~~~~~~~~~~~~~~~~~~~~~

now i get it .. the WA's in the discuss are very useful :-)

and .. with my o(n*k)
i had .. 0.031    264 KB

Edited by author 13.09.2010 22:03

Edited by author 13.09.2010 22:03

Are you sure it's O(n*k)?

I used DFS from every tramstop to find how much it costs for all of friends to meet here.
This test helped me a lot (it's funny to draw circles):

13 5
3 1 2 3
3 4 5 3
3 6 7 3
3 8 9 3
8 10 4 11 6 12 8 13 1

I corrected all mistakes by adding different situations on this tram-map :)