uva :336 - A Node Too Far

#include<cstdio>
#include<vector>
#include<queue>
#include<map>
using namespace std;

map<int,bool>visit;

int bfs(map<int , vector <int > >graph, int source, int ttl)
{
    int count=1,f,node,size;
    queue<int > q;
    map<int,int>level;
    level[source]=ttl;
    visit[source]=true;
    q.push(source);
    while (!q.empty())
    {
        f=q.front();
        q.pop();
        if (level[f]==0) break;
        size=graph[f].size();
        for (int i=0;i<size;i++)
        {
            node=graph[f][i];
            if (visit[node]==false)
            {
                q.push(node);
                visit[node]=true;
                level[node]=level[f]-1;
                count++;
            }
        }
    }
    visit.clear();
    return count;
   
}

int main()
{
    int node,edge,case_no=1,a,b,source,ttl;
    while (scanf("%d",&edge) && edge)
    {
        map <int,vector <int > >graph;
        for (int i=0;i<edge;i++)
        {
            scanf("%d%d",&a,&b);
            graph[a].push_back(b);
            graph[b].push_back(a);
            visit[a]=false;
            visit[b]=false;
        }
       
        while (scanf("%d%d",&source,&ttl)==2)
        {
            if (source==0 && ttl==0) break;
            int visited=bfs(graph,source,ttl);
            printf("Case %d: %d nodes not reachable from node %d with TTL = %d.\n",case_no++,graph.size()-visited,source,ttl);
        }
       
    }
    return 0;
}