A13333. Restoring Permutation

You are given a sequence $b_1, b_2, \ldots, b_n$ . Find the lexicographically minimal permutation $a_1, a_2, \ldots, a_{2n}$ such that $b_i = \min(a_{2i-1}, a_{2i})$ , or determine that it is impossible.

Each test contains one or more test cases. The first line contains the number of test cases $t$ ( $1 \le t \le 100$ ).

The first line of each test case consists of one integer $n$ — the number of elements in the sequence $b$ ( $1 \le n \le 100$ ).

The second line of each test case consists of $n$ different integers $b_1, \ldots, b_n$ — elements of the sequence $b$ ( $1 \le b_i \le 2n$ ).

It is guaranteed that the sum of $n$ by all test cases doesn't exceed $100$ .

For each test case, if there is no appropriate permutation, print one number $-1$ .

Otherwise, print $2n$ integers $a_1, \ldots, a_{2n}$ — required lexicographically minimal permutation of numbers from $1$ to $2n$ .