#P1385B. Restore the Permutation by Merger
Restore the Permutation by Merger
Description
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.
Input
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 $p$.
Output
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.
Samples
5
2
1 1 2 2
4
1 3 1 4 3 4 2 2
5
1 2 1 2 3 4 3 5 4 5
3
1 2 3 1 2 3
4
2 3 2 4 1 3 4 1
1 2
1 3 4 2
1 2 3 4 5
1 2 3
2 3 4 1