Combinations

class Solution {
public:
    vector<vector<int> > combine(int n, int k) {
    vector<vector<int> > vv;
    vector<int> v;
    if(k<=0) return vv;
    if(k==1) {
        for(int k=1;k<=n;k++)
        {v.push_back(k);
         vv.push_back(v);
         v.clear();
        }
        return vv;
     }
     return get_part(1,n,k);
    }
   
   vector<vector<int> > get_part(int m, int n,int k) {
    cout<<"enter"<<m<<" "<<n<<" "<<k<<" "<<endl;
    vector<vector<int> > vv;
    vector<vector<int> > vv1;
    vector<vector<int> > vv2;
    vector<int> v;
    if(k<=0) return vv;
    if(k>n) return vv;
    if(k==n) {
        for(int kk=1;kk<=n;kk++)
        {
            v.push_back(kk);
        }
        vv.push_back(v);
        return vv;
    }
    if(k==1) {   //here is key
        for(int kk=1;kk<=n;kk++)
        {v.push_back(kk);
            vv.push_back(v);
            v.clear();
        }
        for(int idx=0;idx<vv.size();idx++)
        {
            for(int idx_j=0;idx_j<vv[idx].size();idx_j++)
                cout<<vv[idx][idx_j]<<"---";
            cout<<endl;
        }
        return vv;
    }

    int i=n;
//    for(int i=n;i>=k;i--)
    {
        vv2=get_part(m,i-1,k-1);
        for(int  j=0;j<vv2.size();j++)
        {
            vv2[j].push_back(i);
        }
        for(int  j=0;j<vv2.size();j++)
            vv.push_back(vv2[j]);
    
         vv1=get_part(m,i-1,k);
    
        for(int  j=0;j<vv1.size();j++)
            vv.push_back(vv1[j]);
    
        
    }
    return vv;
}
};