491. Increasing Subsequences

class Solution {
public:
    typedef vector<int> VI;
    typedef vector<VI> VVI;
    void traverse(VVI &out, VI &item, VI &src, int i)
    {
        unordered_set<int> si;
        for(int j=i;j<src.size();++j)
        {
            if((item.empty()||src[j]>=item.back())&&si.find(src[j])==si.end())
            {
                item.push_back(src[j]);
          　　　 if(item.size()>1)out.push_back(item);
                traverse(out,item,src,j+1);
                item.pop_back();
                si.insert(src[j]);
            }
        }
    }
    vector<vector<int>> findSubsequences(vector<int>& nums) {
        VVI ret;
        VI item;
        traverse(ret,item,nums, 0);
        return ret;
    }
};