How to Improve?

So I'm working on a project that solves the Kevin Bacon problem. The code works fine for a small file size, but I have to read in the entire IMDB movie database file, which contains thousands of movies. I have a graph where the vertices are the actors. I then create edges between the actors if they were in the same movie. However, I think my problem lies in creating the vertices because it is creating a string for each vertex, and so it quickly runs out of memory.

Code:

#ifndef GRAPHSTUFF_H_ #define GRAPHSTUFF_H_ #include <iostream> #include <string> #include <sstream> #include <fstream> #include <list> #include <vector> using namespace std; struct Vertex; struct Edge { // First vertex in edge is implicit Vertex *dest; // Second vertex in edge double cost; // Edge cost Edge( Vertex *d = 0, double c = 0.0 ) : dest( d ), cost( c ) { } }; // Structure stored in priority queue for Dijkstra's algorithm. struct Path { Vertex *dest; // w double cost; // d(w) Path( Vertex *d = 0, double c = 0.0 ) : dest( d ), cost( c ) { } bool operator> ( const Path & rhs ) const { return cost > rhs.cost; } bool operator< ( const Path & rhs ) const { return cost < rhs.cost; } }; const int INFINITY = std::numeric_limits<int>::max(); // Basic info for each vertex. struct Vertex { std::string name; // Vertex name vector<Edge> adj; // Adjacent vertices (and costs) double dist; // Cost Vertex *prev; // Previous vertex on shortest path int scratch; // Extra variable used in algorithm Vertex( const std::string & nm ) : name( nm ) { reset( ); } void reset( ) { dist = INFINITY; prev = NULL; scratch = 0; } }; #endif /*GRAPHSTUFF_H_*/

Is there any way to improve this?