CF1526A.Mean Inequality

传统题 时间 2000 ms 内存 256 MiB 3 尝试 1 已通过 1 标签

Mean Inequality

You are given an array aa of 2n2n distinct integers. You want to arrange the elements of the array in a circle such that no element is equal to the the arithmetic mean of its 22 neighbours.

More formally, find an array bb, such that:

  • bb is a permutation of aa.
  • For every ii from 11 to 2n2n, bibi1+bi+12b_i \neq \frac{b_{i-1}+b_{i+1}}{2}, where b0=b2nb_0 = b_{2n} and b2n+1=b1b_{2n+1} = b_1.

It can be proved that under the constraints of this problem, such array bb always exists.

Input

The first line of input contains a single integer tt (1t1000)(1 \leq t \leq 1000) — the number of testcases. The description of testcases follows.

The first line of each testcase contains a single integer nn (1n25)(1 \leq n \leq 25).

The second line of each testcase contains 2n2n integers a1,a2,,a2na_1, a_2, \ldots, a_{2n} (1ai109)(1 \leq a_i \leq 10^9) — elements of the array.

Note that there is no limit to the sum of nn over all testcases.

Output

For each testcase, you should output 2n2n integers, b1,b2,b2nb_1, b_2, \ldots b_{2n}, for which the conditions from the statement are satisfied.

Note

In the first testcase, array [3,1,4,2,5,6][3, 1, 4, 2, 5, 6] works, as it's a permutation of [1,2,3,4,5,6][1, 2, 3, 4, 5, 6], and 3+421\frac{3+4}{2}\neq 1, 1+224\frac{1+2}{2}\neq 4, 4+522\frac{4+5}{2}\neq 2, 2+625\frac{2+6}{2}\neq 5, 5+326\frac{5+3}{2}\neq 6, 6+123\frac{6+1}{2}\neq 3.

Samples

3
3
1 2 3 4 5 6
2
123 456 789 10
1
6 9
3 1 4 2 5 6
123 10 456 789
9 6

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