CF1741B.Funny Permutation
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
A sequence of n numbers is called permutation if it contains all numbers from 1 to n exactly once. For example, the sequences [3,1,4,2] , [ 1 ] and [2,1] are permutations, but [1,2,1] , [0,1] and [1,3,4] are not.
For a given number n you need to make a permutation p such that two requirements are satisfied at the same time:
- For each element pi , at least one of its neighbors has a value that differs from the value of pi by one. That is, for each element pi ( 1≤i≤n ), at least one of its neighboring elements (standing to the left or right of pi ) must be pi+1 , or pi−1 .
- the permutation must have no fixed points. That is, for every i ( 1≤i≤n ), pi=i must be satisfied.
Let's call the permutation that satisfies these requirements funny.
For example, let n=4 . Then [ 4,3,1,2 ] is a funny permutation, since:
- to the right of p1=4 is p2=p1−1=4−1=3 ;
- to the left of p2=3 is p1=p2+1=3+1=4 ;
- to the right of p3=1 is p4=p3+1=1+1=2 ;
- to the left of p4=2 is p3=p4−1=2−1=1 .
- for all i is pi=i .
For a given positive integer n , output any funny permutation of length n , or output -1 if funny permutation of length n does not exist.
输入格式
The first line of input data contains a single integer t ( 1≤t≤104 ) — the number of test cases.
The description of the test cases follows.
Each test case consists of f single line containing one integer n ( 2≤n≤2⋅105 ).
It is guaranteed that the sum of n over all test cases does not exceed 2⋅105 .
输出格式
For each test case, print on a separate line:
- any funny permutation p of length n ;
- or the number -1 if the permutation you are looking for does not exist.
输入输出样例
输入#1
5 4 3 7 5 2
输出#1
3 4 2 1 -1 6 7 4 5 3 2 1 5 4 1 2 3 2 1
说明/提示
The first test case is explained in the problem statement.
In the second test case, it is not possible to make the required permutation: permutations [1,2,3] , [1,3,2] , [2,1,3] , [3,2,1] have fixed points, and in [2,3,1] and [3,1,2] the first condition is met not for all positions.