不会，求答案 v

#include <iostream> using namespace std; int main(){ string s; string 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(s2>s1){ cout<<s2<<s1; } else if(s2<s1){ cout<<s1<<s2; } return 0; }