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CF1691B.Shoe Shuffling
Shoe Shuffling
A class of students got bored wearing the same pair of shoes every day, so they decided to shuffle their shoes among themselves. In this problem, a pair of shoes is inseparable and is considered as a single object.
There are students in the class, and you are given an array in non-decreasing order, where is the shoe size of the -th student. A shuffling of shoes is valid only if no student gets their own shoes and if every student gets shoes of size greater than or equal to their size.
You have to output a permutation of denoting a valid shuffling of shoes, where the -th student gets the shoes of the -th student (). And output if a valid shuffling does not exist.
A permutation is an array consisting of distinct integers from to in arbitrary order. For example, is a permutation, but is not a permutation ( appears twice in the array) and is also not a permutation ( but there is in the array).
Input
Each test contains multiple test cases. The first line contains a single integer () — the number of test cases. Description of the test cases follows.
The first line of each test case contains a single integer () — the number of students.
The second line of each test case contains integers (, and for all , ) — the shoe sizes of the students.
It is guaranteed that the sum of over all test cases does not exceed .
Output
For each test case, print the answer in a single line using the following format.
If a valid shuffling does not exist, print the number as the answer.
If a valid shuffling exists, print space-separated integers — a permutation of denoting a valid shuffling of shoes where the -th student gets the shoes of the -th student. If there are multiple answers, then print any of them.
Note
In the first test case, any permutation of where would represent a valid shuffling since all students have equal shoe sizes, and thus anyone can wear anyone's shoes.
In the second test case, it can be shown that no valid shuffling is possible.
Samples
2
5
1 1 1 1 1
6
3 6 8 13 15 21
5 1 2 3 4
-1
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