Lintcode乱序字符串（时间过长）

class Solution {public:        /**     * @param strs: A list of strings     * @return: A list of strings     */    vector<string> anagrams(vector<string> &strs) {        // write your code here        vector<string>::iterator beg=strs.begin(),iter,iter1,                                 end=strs.end();        vector<string> result;        set<int> record;   int flag;                                         for(iter=beg;iter!=end;iter++){            if(!record.count(iter-beg)){                flag=0;  string s1=*iter; std::sort(s1.begin(),s1.end());                for(iter1=iter+1;iter1!=end;iter1++){                    string s2=*iter1;                    std::sort(s2.begin(),s2.end());                    if(s1==s2)  {                        ++flag;                        if(flag==1)  { result.push_back(*iter);result.push_back(*iter1);}                        else  result.push_back(*iter1);                        record.insert(iter1-beg);                    }                }            }        }                return result;            }};