Building symbol table using hash table

[xoxococoa]

I'm trying to build a symbol table using hash table. The general idea is
int alpha;
2 int beta;
3 alpha = 0; // the alpha declared in line 1
4 beta = 0; // the beta declared in line 2
5 gamma = 0; // Error! gamma hasn't been declared.
6 {
7 int beta; // This beta shadows the one declared in line 2.
8 int gamma;
9 alpha = 0; // the alpha declared in line 1
10 beta = 0; // the beta declared in line 7
11 gamma = 0; // the gamma declared in line 8
12 }

and so on. You only can use vector, list, stack, and queue library and try to make it as fast as it can.
My idea was on each scope, I declare hashtable in the list and save all the information to that table, and whenever I have new scope, I push_back new hashtable into the list.
But it seems like this approach is very slow when the program is looking for on item that is out of scope far far away since you have to look for each scope to find the item.

Do you guys have any idea to implement this scope that is way faster than this? It should be way faster cause my implementation is slower than the "slow version they provided"

Thanks alot!

[onur]

It would be helpful if you could post your version!

Speed also depends on the expected number of symbols.
E.g. linear searching is fine if you have few symbols.