Data structure for matching sets

Question

I have an application where I have a number of sets. A set might be
{4, 7, 12, 18}
unique numbers and all less than 50.

I then have several data items:
1 {1,

Answer 1

I'm surprised no one has mentioned that the STL contains an algorithm to handle this sort of thing for you. Hence, you should use includes. As it describes it performs at most 2*(N+M)-1 comparisons for a worst case performance of O(M+N).

Hence:

bool isContained = includes( myVector.begin(), myVector.end(), another.begin(), another.end() );

if you're needing O( log N ) time, I'll have to yield to the other responders.