1707B - Difference Array - CodeForces Solution

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])