A. Entertainment in MAC

time limit per test

1 second

memory limit per test

256 megabytes

Congratulations, you have been accepted to the Master's Assistance Center! However, you were extremely bored in class and got tired of doing nothing, so you came up with a game for yourself.

You are given a string ss and an even integer nn. There are two types of operations that you can apply to it:

  1. Add the reversed string ss to the end of the string ss (for example, if s=s= cpm, then after applying the operation s=s= cpmmpc).
  2. Reverse the current string ss (for example, if s=s= cpm, then after applying the operation s=s= mpc).

It is required to determine the lexicographically smallest†† string that can be obtained after applying exactly nn operations. Note that you can apply operations of different types in any order, but you must apply exactly nn operations in total.

††A string aa is lexicographically smaller than a string bb if and only if one of the following holds:

  • aa is a prefix of bb, but a≠ba≠b;
  • in the first position where aa and bb differ, the string aa has a letter that appears earlier in the alphabet than the corresponding letter in bb.

Input

Each test consists of multiple test cases. The first line contains a single integer tt (1≤t≤5001≤t≤500) --- the number of test cases. The description of the test cases follows.

The first line of each test case contains a single even integer nn (2≤n≤1092≤n≤109) --- the number of operations applied to the string ss.

The second line of each test case contains a single string ss (1≤|s|≤1001≤|s|≤100), consisting of lowercase English letters, --- the string to which the operations are applied.

Output

For each test case, output a single line --- the lexicographically smallest string that can be obtained after applying exactly nn operations.

Example

Input

Copy

复制代码

5

4

cpm

2

grib

10

kupitimilablodarbuz

1000000000

capybara

6

abacaba

Output

Copy

复制代码
cpm
birggrib
kupitimilablodarbuz
arabypaccapybara
abacaba

Note

In the first test case, you can apply the operation of the second type (i.e., reverse the string ss) 44 times. Then the string ss will remain equal to cpm.

In the second test case, you can do the following:

  • Apply the operation of the second type, after which ss will become equal to birg.
  • Apply operation of the first type (i.e., add the reversed string ss to the end of the string ss), after which ss will become equal to birggrib.

解题说明:此题是一道字符串题,找规律能发现如果这个字符串翻转后更大,那么我们就可以进行n次翻转,这样最终的字符串就是原先的字符串,也就实现最小了。如果这个字符串s在反转后更小了,那么我们就必须执行奇数次翻转,才能保证这个s最终是较小的。但题目中说n是偶数,所以就至少一次拼接操作,拼接操作进行的越少越好, 因此翻转n − 1次,拼接一次。

cpp 复制代码
#include<iostream>
#include <cstring>
#include <algorithm>
#include<vector>
using namespace std;

void solve() 
{
	int n;
	cin >> n;
	string str;
	cin >> str;
	string rs = str;
	reverse(rs.begin(), rs.end());
	if (rs < str) 
	{
		cout << (rs + str) << '\n';
	}
	else
	{
		cout << str << '\n';
	}
}
int main() 
{
	int T = 1;
	cin >> T;
	while (T--)
	{
		solve();
	}
	return 0;
}
相关推荐
北域码匠8 小时前
高通滤波算法深度解析(High-Pass Filter)
stm32·算法·c#·数字信号处理·嵌入式开发·滤波算法·高通滤波
指掀涛澜天下惊8 小时前
强化学习进阶篇八 策略梯度算法
深度学习·学习·算法·强化学习
乌萨奇也要立志学C++8 小时前
【洛谷】kmp算法
开发语言·算法
禹凕9 小时前
Dijkstra算法详解与应用
python·算法
YaraMemo9 小时前
元启发式算法框架
人工智能·算法·5g·信息与通信·启发式算法·信号处理
weixin_3077791310 小时前
一维无粘 Burgers 方程的激波形成问题:MacCormack 格式求解
c++·算法·matlab
HugoStudio_SWAN10 小时前
洛谷 B4500 / B4449 / B3843 凯撒密码、密码强度与密码合规——加密与安全的三道门
c++·学习·程序人生·算法·安全
枫叶林FYL11 小时前
【群体智能集群控制工程实践】第3章 一致性协同算法
算法
禹凕11 小时前
滑动窗口算法实战指南
python·算法
DisonTangor11 小时前
【腾讯混元雪耻归来】 Hy4 preview:770B 参数 MoE 旗舰模型,1M 上下文全面开源
人工智能·算法·开源·aigc·腾讯云·腾讯云ai代码助手