CF1203A.Circle of Students

普及/提高-

通过率:0%

AC君温馨提醒

该题目为【codeforces】题库的题目,您提交的代码将被提交至codeforces进行远程评测,并由ACGO抓取测评结果后进行展示。由于远程测评的测评机由其他平台提供,我们无法保证该服务的稳定性,若提交后无反应,请等待一段时间后再进行重试。

题目描述

There are nn students standing in a circle in some order. The index of the ii -th student is pip_i . It is guaranteed that all indices of students are distinct integers from 11 to nn (i. e. they form a permutation).

Students want to start a round dance. A clockwise round dance can be started if the student 22 comes right after the student 11 in clockwise order (there are no students between them), the student 33 comes right after the student 22 in clockwise order, and so on, and the student nn comes right after the student n1n - 1 in clockwise order. A counterclockwise round dance is almost the same thing — the only difference is that the student ii should be right after the student i1i - 1 in counterclockwise order (this condition should be met for every ii from 22 to nn ).

For example, if the indices of students listed in clockwise order are [2,3,4,5,1][2, 3, 4, 5, 1] , then they can start a clockwise round dance. If the students have indices [3,2,1,4][3, 2, 1, 4] in clockwise order, then they can start a counterclockwise round dance.

Your task is to determine whether it is possible to start a round dance. Note that the students cannot change their positions before starting the dance; they cannot swap or leave the circle, and no other student can enter the circle.

You have to answer qq independent queries.

输入格式

The first line of the input contains one integer qq ( 1q2001 \le q \le 200 ) — the number of queries. Then qq queries follow.

The first line of the query contains one integer nn ( 1n2001 \le n \le 200 ) — the number of students.

The second line of the query contains a permutation of indices p1,p2,,pnp_1, p_2, \dots, p_n ( 1pin1 \le p_i \le n ), where pip_i is the index of the ii -th student (in clockwise order). It is guaranteed that all pip_i are distinct integers from 11 to nn (i. e. they form a permutation).

输出格式

For each query, print the answer on it. If a round dance can be started with the given order of students, print "YES". Otherwise print "NO".

输入输出样例

  • 输入#1

    5
    4
    1 2 3 4
    3
    1 3 2
    5
    1 2 3 5 4
    1
    1
    5
    3 2 1 5 4
    

    输出#1

    YES
    YES
    NO
    YES
    YES
    
首页