manager-employee
Source: hackerearth
Difficulty: UNKNOWN_DIFFICULTY

A company manager gave projects to the employees of his company. The employees have to form a team of two for doing the project. The manager left the employees to decide the teams. The number of employees in a company will be even.

Every employee has knowledge level.It tells how much knowledge each employee has.The knowledge level of team is the sum of the knowledge level of both the employees. The.The employees decide to form groups such that the difference between the team with highest knowledge and the one with lowest knowledge is minimum.

Input:

First line of the input will contain number of test cases t.

In the next t lines the first number is n the number of employees in the company followed by n integers denoting the knowledge levels of the n employees.

Output:

Your output should be a single line containing the lowest possible difference between the team with highest knowledge and the one with lowest knowledge.

SAMPLE INPUT
2
4 2 6 4 3        
6 1 1 1 1 1 1

SAMPLE OUTPUT
1
0

Explanation

Explanation:

Input Constraints are:

1 ≤ t ≤ 100   

1 ≤ n ≤ 100    

1 ≤ knowledge level ≤ 10000


for i in range(eval(input())):
	s=[]
	a=list(map(int,input().split()))
	n=a[0]
	a=a[1:]
	a.sort()
	for i in range(n/2):
		s.append(a[i]+a[n-1-i])
	s.sort()
	l=len(s)
	print(s[l-1]-s[0])