unordered_map

mateifl 2013-11-05 19:59:44 UTC #1

Can I use unordered_map with a c++ submission ?
As far as I know gcc 4.3 and above has support for it.
Can anyone confirm?
Thank you.

leppyr64 2013-11-05 20:08:56 UTC #2

Have you tried it? I don't see why it should not work. What purpose do you want to use it for that a normal map would not fulfill?

mateifl 2013-11-05 20:20:30 UTC #3

AFAIK, the normal map is backed up by a tree (red-black I think), which makes insertion and find operations O(logN).
unordered_map is a hash table so O(1).
And you are right, I should try first

leppyr64 2013-11-05 20:59:56 UTC #4

Some food for thought:
stackoverflow.com/questions/2196 ... ivial-keys

mateifl 2013-11-08 12:19:58 UTC #5

Thank you for the link.

About using :
I got AC for a problem (PPATH) without using unsorted_map.
Then just to test, I added

include

and the result was compilation error.
So I would say it's not working.
Also on ideone using generates an error in the preprocessing step.

EDIT: corrected the mistake, I used , which does not even exist in STL, instead of .

leppyr64 2013-11-08 13:02:40 UTC #6

unordered != unsorted