int Q[8] = {-1,-1,-1,0,0,1,1,1};
int W[8] = {-1,0,1,-1,1,-1,0,1};

void dfs(int x, int y)
{
    //.....
    for (int i = 0; i < 8; i++)
    {
        int a = x + Q[i], b = y + W[i];
        //(a,b) es vecino de (x,y)
        /*
        .
        .
        .
        */
    }
}