Adjacency list implementation using stl multimaps

[Prakash Premkumar]

Hi,
I'm trying to implement some graph algorithms in c++. I'm aware of the time-complexity trade off which arises when we choose between adjacency matrices and adjacency lists to represent a graph.

I'm trying to implement adjacency list using STL multimaps.Below is my BFS code which uses it:

#include<stdio.h>
#include<iostream>
#include<queue>
#include<list>
#include <map>

#define WHITE 0
#define BLACK 1
#define GRAY  2

using namespace std;

struct vertex {
    int color,d,pred,name,part;
}v[10];

    multimap< int,int > m;
    multimap< int,int > :: iterator it1;
    multimap< int,int > :: iterator it2;

void BFS(int n) {
    int i;
    for(i=2;i<=n;i++) {
        v[i].color=WHITE;
        v[i].d=-100;
        v[i].pred=-10;
        v[i].name=i;
    }

    v[1].color=GRAY;
    v[1].d=0;
    v[1].pred=-10;
    v[1].name=1;

queue<vertex> q;
q.push(v[1]);
printf("1 ");
vertex u;
while(!q.empty()) {
     u=q.front();
     q.pop();
   
     it1=m.lower_bound(u.name);
     it2=m.upper_bound(u.name);

     while(it1!=it2) {

         i=it1->second;
         if(v[i].color==WHITE){
                 v[i].color=GRAY;
                 v[i].d=u.d+1;
                 v[i].pred=u.name;
                 q.push(v[i]);
                 printf("%d ",v[i].name);
             }
         it1++;

     }
     u.color=BLACK;

   }
}
int main() {
   

    freopen("in.in","r",stdin);

    int i,j,n;
    cout<<"vertex count:";
    cin>>n;
    
    cout<<"\nEdges: ";
    cin>>i>>j;
    m.insert( pair<int ,int>(i,j));
     m.insert( pair<int ,int>(j,i));
    while(i!=-1 && j!=-1) {
          m.insert( pair<int ,int>(i,j));
          m.insert( pair<int ,int>(j,i));
         cout<<"\nEdges: ";
         cin>>i>>j;

    }

   /* cout<<"Adjacency list";
    for(it1=m.begin();it1!=m.end();it1++) {
        cout<<"\n"<<it1->first<<" "<<it1->second;
    }*/
    
       cout<<endl<<"BFS"<<"\n";
   BFS(n);

   return 0;
}

and here is my code without using multimaps. using an adjacency matrix,

#include<stdio.h>
#include<iostream>
#include<queue>

#define WHITE 0
#define BLACK 1
#define GRAY  2

using namespace std;

struct vertex {
    int color,d,pred,name,part;
}v[10];

void BFS(int n,int adj[][10]) {
    int i;
    for(i=2;i<=n;i++) {
        v[i].color=WHITE;
        v[i].d=-100;
        v[i].pred=-10;
        v[i].name=i;
    }

    v[1].color=GRAY;
    v[1].d=0;
    v[1].pred=-10;
    v[1].name=1;

queue<vertex> q;
q.push(v[1]);
printf("1 ");
vertex u;
while(!q.empty()) {
     u=q.front();
     q.pop();
     //printf("%d ",u.name);
     for(i=1;i<=n;i++) {
         if(adj[u.name][i]==1) {
             if(v[i].color==WHITE){
                 v[i].color=GRAY;
                 v[i].d=u.d+1;
                 v[i].pred=u.name;
                 q.push(v[i]);
                 printf("%d ",v[i].name);
             }


         }

         u.color=BLACK;
     }



}


}
int main() {
   int adj[10][10],n;
   printf("\nNo of edges:");
   scanf("%d",&n);
   int x,y,i,j;
   for(i=1;i<=n;i++)
       for(j=1;j<=n;j++)
           adj[i][j]=0;


   scanf("%d %d",&x,&y);
       adj[x][y]=1;
       adj[y][x]=1;
   while(x!=0 && y!=0) {
       scanf("%d %d",&x,&y);
       adj[x][y]=1;
       adj[y][x]=1;

   }

   for(i=1;i<=n;i++){ printf("\n");
       for(j=1;j<=n;j++)
           printf("%d ",adj[i][j]);
   }
       cout<<endl<<"BFS"<<"\n";
   BFS(n,adj);

   return 0;
}

I'm not sure whether the adjacency list implementation which uses multimaps is more efficient than the matrix implementation.Please help me find out which method is more efficient and please suggest me a method to implement adjacency list using STL containers.
Thank you
prakashprax