Choosing a STL container with uniqueness and which keeps insertion ordering

Question

I am unable to decide which STL container to use in the following case:

1. I want to preserve the order of insertion of the elements
2. The elements in the

Answer 1

Boost MultiIndex should be able to do exactly what you want - you can just use one sequenced index to get the "ordered by insertion order" requirement, and either a hashed_unique or ordered_unique index to get the uniqueness requirement.