zoj 1990 Subway Tree Systems

zoj 1990 Subway Tree Systems

#include<iostream>#include<algorithm>#include<string.h>#include<vector>using namespace std;string DFS(string s){    if(s=="01")return s;    else    {        s=s.substr(1,s.size()-2);        string str="";        vector <string> vs;        int cnt=0,start=0;        for(int i=0;i<s.size();i++)        { cnt+=(s[i]=='0'?1:-1); if(!cnt) {     vs.push_back(DFS(s.substr(start,i-start+1)));     start=i+1; }        }        sort(vs.begin(),vs.end());        str+='0';        for(int j=0;j<vs.size();j++) str+=vs[j];        str+='1';        return str;    }}int main(){    string s1,s2;    int cas;    cin>>cas;    while(cas--)    {        cin>>s1>>s2;        s1="0"+s1+"1";        s2="0"+s2+"1";        s1=DFS(s1);        s2=DFS(s2);        if(s1==s2)cout<<"same"<<endl;        else cout<<"different"<<endl;    }}