from bisect import bisect as b
for _ in range(int(input())):
n=int(input())
l=list(map(int,input().split()))
for j in range(1,n):
k=[]
for i in range(1,len(l)):
k.append(l[i]-l[i-1])
k.sort()
l=k[b(k,0):]
if len(l)<n-j:
l.insert(0,0)
if len(l)==1:
print(l[0])628. Maximum Product of Three Numbers | 1526A - Mean Inequality |
1526B - I Hate 1111 | 1881. Maximum Value after Insertion |
237. Delete Node in a Linked List | 27. Remove Element |
39. Combination Sum | 378. Kth Smallest Element in a Sorted Matrix |
162. Find Peak Element | 1529A - Eshag Loves Big Arrays |
19. Remove Nth Node From End of List | 925. Long Pressed Name |
1051. Height Checker | 695. Max Area of Island |
402. Remove K Digits | 97. Interleaving String |
543. Diameter of Binary Tree | 124. Binary Tree Maximum Path Sum |
1465. Maximum Area of a Piece of Cake After Horizontal and Vertical Cuts | 501A - Contest |
160A- Twins | 752. Open the Lock |
1535A - Fair Playoff | 1538F - Interesting Function |
1920. Build Array from Permutation | 494. Target Sum |
797. All Paths From Source to Target | 1547B - Alphabetical Strings |
1550A - Find The Array | 118B - Present from Lena |