The easy problem in SRM 685 is the N-th time I failed because of using
__builtin_popcount instead of
__builtin_popcountll. As a result, a new line has been added to my template code:
#define __builtin_popcount __builtin_popcountll
Btw, does anyone have an idea why C++ doesn't merge the 2 above functions into one to avoid such silly mistakes?