A13606. Restore the Permutation by Merger

A permutation of length $n$ is a sequence of integers from $1$ to $n$ of length $n$ containing each number exactly once. For example, $[1]$ , $[4, 3, 5, 1, 2]$ , $[3, 2, 1]$ are permutations, and $[1, 1]$ , $[0, 1]$ , $[2, 2, 1, 4]$ are not.

There was a permutation $p[1 \dots n]$ . It was merged with itself. In other words, let's take two instances of $p$ and insert elements of the second $p$ into the first maintaining relative order of elements. The result is a sequence of the length $2n$ .

For example, if $p=[3, 1, 2]$ some possible results are: $[3, 1, 2, 3, 1, 2]$ , $[3, 3, 1, 1, 2, 2]$ , $[3, 1, 3, 1, 2, 2]$ . The following sequences are not possible results of a merging: $[1, 3, 2, 1, 2, 3$ \], \[ $3, 1, 2, 3, 2, 1]$ , $[3, 3, 1, 2, 2, 1]$ .

For example, if $p=[2, 1]$ the possible results are: $[2, 2, 1, 1]$ , $[2, 1, 2, 1]$ . The following sequences are not possible results of a merging: $[1, 1, 2, 2$ \], \[ $2, 1, 1, 2]$ , $[1, 2, 2, 1]$ .

Your task is to restore the permutation $p$ by the given resulting sequence $a$ . It is guaranteed that the answer exists and is unique.

You have to answer $t$ independent test cases.

The first line of the input contains one integer $t$ ( $1 \le t \le 400$ ) — the number of test cases. Then $t$ test cases follow.

The first line of the test case contains one integer $n$ ( $1 \le n \le 50$ ) — the length of permutation. The second line of the test case contains $2n$ integers $a_1, a_2, \dots, a_{2n}$ ( $1 \le a_i \le n$ ), where $a_i$ is the $i$ -th element of $a$ . It is guaranteed that the array $a$ represents the result of merging of some permutation $p$ with the same permutation $p$ .

For each test case, print the answer: $n$ integers $p_1, p_2, \dots, p_n$ ( $1 \le p_i \le n$ ), representing the initial permutation. It is guaranteed that the answer exists and is unique.