DFS

dfs.c

void dfs(int start, string &s, 
         vector<string> &tmp, vector<vector<string> > &result)
{
        if (start == s.size()) {
                result.push_back(tmp);
                return ;
        }

        for (int i = start; i < s.size(); i++) {
                tmp.push_back(s.substr(start, i-start+1));
                dfs(i+1, s, tmp, result);
                tmp.pop_back();
        }

}