Combinations

class Solution 

{

public:

    vector<vector<int> > combine(int n, int k) 

    {

        vector<int> vecTmp;

        m_vecRet.clear();

        combination(1, n, vecTmp, k);

        return m_vecRet;

    }

private:

    void combination(int from, int to, vector<int> &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<vector<int> > m_vecRet;

};

转载于:https://www.cnblogs.com/codingmylife/archive/2012/09/01/2667056.html