字符串的剥离重组

#include<iostream>
using namespace std;
int main(){
string s,s1="",s2="";
cin>>s;
for(int i=0;i<s.size();i++){
if(i%2==0){
s1=s1+s[i];
}else{
s2=s2+s[i];
}
}
if(s1<s2){
s2=s2+s1;
cout<<s2;
}else{
s1=s1+s2;
cout<<s1;
}

}