class Solution

{

public:

vector
      
       
         > combine(int n, int k)
       
      

{

vector
      
        vecTmp;
      

m_vecRet.clear();

combination(1, n, vecTmp, k);

return m_vecRet;

}

private:

void combination(int from, int to, vector
      
        &curr, int k)
      

{

if (k == 0)

{

m_vecRet.push_back(curr);

}

else if (from > to)

{

return;

}

else

{

curr.push_back(from);

combination(from + 1, to, curr, k - 1);

curr.pop_back();

combination(from + 1, to, curr, k);

}

}

private:

vector
      
       
         > m_vecRet;
       
      

};