Codeforces Round #490 (Div. 3) B. Reversing Encryption

B. Reversing Encryption
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

A string ss of length nn can be encrypted by the following algorithm:

  • iterate over all divisors of nn in decreasing order (i.e. from nn to 11),
  • for each divisor dd, reverse the substring s[1d]s[1…d] (i.e. the substring which starts at position 11 and ends at position dd).

For example, the above algorithm applied to the string ss="codeforces" leads to the following changes: "codeforces"secrofedoc "orcesfedoc "rocesfedoc "rocesfedoc" (obviously, the last reverse operation doesn't change the string because d=1d=1).

You are given the encrypted string tt. Your task is to decrypt this string, i.e., to find a string ss such that the above algorithm results in string tt. It can be proven that this string ss always exists and is unique.

Input

The first line of input consists of a single integer nn (1n1001≤n≤100) — the length of the string tt. The second line of input consists of the string tt. The length of tt is nn, and it consists only of lowercase Latin letters.

Output

Print a string ss such that the above algorithm results in tt.

Examples
input
Copy
10
rocesfedoc
output
Copy
codeforces
input
Copy
16
plmaetwoxesisiht
output
Copy
thisisexampletwo
input
Copy
1
z
output
Copy
z
Note

The first example is described in the problem statement.


题目大意就是给你一串长为n的加密后的字符串,你要做的就是解密。

以第二组样例为例

plmaetwoxesisiht  -> thisisexampletwo 

这个过程就是先把整个加密后的串分为两半再分再分直到分到只剩两个

plmaetwoxesisiht 变为 pl

翻转变为 lp

然后四个元素时是 lpma

翻转变为 ampl

八个元素时是 ampletwo

翻转变为 owtelpma

十六个元素时是 owtelpmaxesisiht

翻转变为 thisisexampletwo  得到答案

(做题时想到递归和栈,结果脑子抽了越想越复杂= =,但还是看了dalao的代码才恍然大悟,哪有这么复杂啊...)

代码如下:

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

int main(){
    int n ;
    while ( cin >> n ){
        string str ;
        cin >> str;
        for ( int i = 1 ; i <= n ; i ++ ){
            if ( n % i == 0 ){          ///找到2的倍数的位置
                reverse(str.begin() , str.begin() + i) ;
            }
        }
        cout << str << endl ;
    }
    return 0 ;
}


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转载自blog.csdn.net/colpac/article/details/80771742