UVa 336 - A node too far

#include <bits/stdc++.h>
#define fora(i,n) for(int i=0 ; i<n ; i++)
#define pb(x) push_back(x)
using namespace std;

unordered_map <int, vector <int> > adj;
//vector <int> level(35),vis(35);
int level[35],vis[35];
int cs;

int bfs(int src,int ttl) {
    int ans=0;
    vis[src]=1;
    level[src]=0;
    queue <int> q;
    q.push(src);
    while(!q.empty()) {
        int u=q.front();q.pop();
        //unordered_map <int, vector <int> > :: iterator &v;
        for(auto v : adj[u]) {
            if(vis[v]==0) {
                //nd++;
                vis[v]=1;
                level[v]=level[u]+1;
                //cout << (v) << ": " <<  level[v] << endl;
                if(level[v]>ttl) ans++;
                q.push(v);
            }
        }
    }
    return ans;
}

int main() {
    cs=1;
    while(1) {
        int e;
        cin >> e;
        if(e==0) break;
        fora(i,e) {
            int x,y;
            cin >> x >> y;
            adj[x].pb(y);
            adj[y].pb(x);
        }
        for( ; ; cs++) {
            int src,ttl;
            cin >> src >> ttl;
            memset(vis,0,sizeof vis);
            memset(level,-1,sizeof level);
            if(src==0 && ttl==0) {
                cs--;
                break;
            }
            int ans=bfs(src,ttl);
            //cout << bfs(src,ttl) << endl;
            printf("Case %d: %d nodes not reachable from node %d with TTL = %d.\n",cs,ans,src,ttl);
        }
        adj.clear();
    }
    return 0;
}