[Solution] Funny Permutation Codeforces Solution
A sequence of numbers is called permutation if it contains all numbers from to exactly once. For example, the sequences , [] and are permutations, but , and are not.
For a given number you need to make a permutation such that two requirements are satisfied at the same time:
- For each element , at least one of its neighbors has a value that differs from the value of by one. That is, for each element (), at least one of its neighboring elements (standing to the left or right of ) must be , or .
- the permutation must have no fixed points. That is, for every (), must be satisfied.
Let's call the permutation that satisfies these requirements funny.
For example, let . Then [] is a funny permutation, since:
- to the right of is ;
- to the left of is ;
- to the right of is ;
- to the left of is .
- for all is .
For a given positive integer , output any funny permutation of length , or output -1 if funny permutation of length does not exist.
The first line of input data contains a single integer () — the number of test cases.
The description of the test cases follows.
Each test case consists of f single line containing one integer ().
It is guaranteed that the sum of over all test cases does not exceed .
For each test case, print on a separate line:
- any funny permutation of length ;
- or the number -1 if the permutation you are looking for does not exist.
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 , , , have fixed points, and in and the first condition is met not for all positions.
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