Switch bulbs

/****************************************************************************************
   *  Md. Abdulla Al Mamun (Nayon)
   *  ID: 1306001
   *  Session: 2013-2014
   *  Department of Computer Science and Engineering
   *  Begum Rokeya University, Rangpur (BRUR)
   *
   *  Project Name:         Switch Bulbs
   *  File Created on:      Monday, 2015-07-27-23.45.30
   *  Current File:         D:\My Codes\C and C++\Code-Blocks Projects\Switch Bulbs\main.cpp
   *  Language:             English (U.S.)
   *  Encoding:             windows-1252
*****************************************************************************************/
#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <queue>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>

using namespace std;

#define EPS 1e-9
#define MAX 32768

bool isEqual(double a, double b)
{
    return abs(a - b) < EPS;
}

int m;
vector<int> connections[45];
int bfs(char* str)
{
    int visited[MAX+5];
    int level[MAX+5];
    queue<int>Q;
    char *ptr;
    int start = 0, destination = (int)strtol(str, &ptr, 2);

    memset(visited, 0, sizeof(visited));
    Q.push(start);
    visited[start] = 1;
    level[start] = 0;

    while(!Q.empty()){
        int par = Q.front();
        Q.pop();

        for(int i = 0; i < m; i++){//switches 0 to m-1
            int current = par;
            int s = connections[i].size();//number of connected number of bulbs with i th switch
            for(int j = 0; j < s; j++){
                int tog = connections[i][j];
                current ^= (1 << tog);//toggling the tog th bit;
            }
            if(visited[current] == 0){
                visited[current] = 1;
                level[current] = level[par] + 1;
                if(current == destination)return level[current];
                else Q.push(current);
            }
        }
    }
    return -1;
}

int main()
{
    //freopen("in.txt", "r", stdin);
    int t, n, i, j, k, q;
    char dest[20];

    scanf("%d", &t);
    for(int t1 = 1; t1 <= t; t1++){
        scanf("%d %d", &n, &m);
        for(i = 0; i < m; i++){
            scanf("%d", &k);
            while(k--){
                scanf("%d", &j);
                connections[i].push_back(j);//j th bulb is toggled by i th switch
            }
        }
        scanf("%d", &q);
        printf("Case %d:\n", t1);
        while(q--){
            scanf("%s", dest);

            printf("%d\n", bfs(dest));
        }
        printf("\n");
        for(i = 0; i < m; i++)
            connections[i].clear();
    }
    return 0;
}