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;
    }
}