Restore the Permutation

1000ms

262144K

Description:

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 permutation $$$p$$$ of even length $$$n$$$ you can make an array $$$b$$$ of length $$$\frac{n}{2}$$$ such that:

$$$b_i = \max(p_{2i - 1}, p_{2i})$$$ for $$$1 \le i \le \frac{n}{2}$$$

For example, if $$$p$$$ = [$$$2, 4, 3, 1, 5, 6$$$], then:

$$$b_1 = \max(p_1, p_2) = \max(2, 4) = 4$$$
$$$b_2 = \max(p_3, p_4) = \max(3,1)=3$$$
$$$b_3 = \max(p_5, p_6) = \max(5,6) = 6$$$

As a result, we made $$$b$$$ = $$$[4, 3, 6]$$$.

For a given array $$$b$$$, find the lexicographically minimal permutation $$$p$$$ such that you can make the given array $$$b$$$ from it.

If $$$b$$$ = [$$$4,3,6$$$], then the lexicographically minimal permutation from which it can be made is $$$p$$$ = [$$$1,4,2,3,5,6$$$], since:

$$$b_1 = \max(p_1, p_2) = \max(1, 4) = 4$$$
$$$b_2 = \max(p_3, p_4) = \max(2, 3) = 3$$$
$$$b_3 = \max(p_5, p_6) = \max(5, 6) = 6$$$

A permutation $$$x_1, x_2, \dots, x_n$$$ is lexicographically smaller than a permutation $$$y_1, y_2 \dots, y_n$$$ if and only if there exists such $$$i$$$ ($$$1 \le i \le n$$$) that $$$x_1=y_1, x_2=y_2, \dots, x_{i-1}=y_{i-1}$$$ and $$$x_i<y_i$$$.

Input:

The first line of input data contains a single integer $$$t$$$ ($$$1 \le t \le 10^4$$$) — the number of test cases.

The description of the test cases follows.

The first line of each test case contains one even integer $$$n$$$ ($$$2 \le n \le 2 \cdot 10^5$$$).

The second line of each test case contains exactly $$$\frac{n}{2}$$$ integers $$$b_i$$$ ($$$1 \le b_i \le n$$$) — elements of array $$$b$$$.

It is guaranteed that the sum of $$$n$$$ values over all test cases does not exceed $$$2 \cdot 10^5$$$.

Output:

For each test case, print on a separate line:

lexicographically minimal permutation $$$p$$$ such that you can make an array $$$b$$$ from it;
or a number -1 if the permutation you are looking for does not exist.

Sample Input:

Sample Output:

1 4 2 3 5 6 
1 2 3 4 
-1
5 6 3 4 1 2 
-1
1 8 6 7 2 4 3 5

Note:

The first test case is parsed in the problem statement.

Informação

Provedor Codeforces

Código CF1759G