#描述#
There are N (2<=N<=200,000) real numbers. Find the max interval between the adjacent numbers.

#格式#
##输入格式##
The first line is the number of cases. Following is the cases:
Line one: N;
Line two: N real numbers.

##输出格式##
The output contains a single line with the max interval, rounded to the third decimal.

#样例1#
##样例输入1##

1
5
2.3 3.1 7.5 1.5 6.3

##样例输出1##

3.200

#限制#
1000ms
32768KB

#提示#

#来源#
lily