UVa - 11192 - Group Reverse

#include <iostream>
#include <cstdio>
#include <string>
using namespace std;

int main(){
    string s, rev_s;
    int l, a, n;
    while(cin >> n){
        if(n == 0)break;
        cin >> s;
        a = s.size();
        l = a / n;
        for(int j = l; j <= a; j += l)
            for(int i = j-1; i >= j-l; i--){
                rev_s.push_back(s[i]);
            }
        cout << rev_s << endl;
        s.clear();rev_s.clear();
    }
    return 0;
}