Codeforces Round 623 (Div. 2, based on VK Cup 2019-2020 - Elimination Round, Engine)
C
Restoring Permutation
Codeforces
1200
原题
← BD →
翻译中…

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.

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Input

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

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

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

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

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Output

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

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

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样例

Input #1
5
1
1
2
4 1
3
4 1 3
4
2 3 4 5
5
1 5 7 2 8
Output #1
1 2
-1
4 5 1 2 3 6
-1
1 3 5 6 7 9 2 4 8 10
InputCopy OutputCopy
题目信息
题号
1315C
时间限制
1 s
内存限制
256 MB
标签
贪心

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。