第二题100% #include<iostream> #include<cmath> #include<algorithm> using namespace std; int main(){     string s;     cin>>s;     int k;     cin>>k;     string s1;     int len=s.length()/(2*k);     //cout<<len<<endl;     for(int i=0;i<len;i++){         for(int j=i*2*k+k-1;j>=i*2*k;j--){             s1+=s[j];         }         int cnt=0;         for(int j=i*2*k;j<i*2*k+k;j++){             s[j]=s1[cnt++];         }         s1.clear();     }     if(s.length()%(2*k)==0) cout<<s<<endl;     else {         s1.clear();          int j=len*2*k;          for(int i=j;i<j+k&&i<s.length();i++){              s1+=s[i];          }           reverse(s1.begin(),s1.end());          int cnt=0;          for(int i=j;i<j+k&&i<s.length();i++){              s[i]=s1[cnt++];          }      cout<<s<<endl;     } }