B"You are given an integer array a_1, a_2, ... , a_n , all its elements are distinct. First, you are asked to insert one more integer a_{n+1} into this array. a_{n+1} should not be equal to any of a_1, a_2, ... , a_n . Then, you will have to make all elements of the array equal. At the start, you choose a positive integer x ( x > 0 ). In one operation, you add x to exactly one element of the array. Note that x is the same for all operations. What's the smallest number of operations it can take you to make all elements equal, after you choose a_{n+1} and x ? The first line contains a single integer t ( 1 <= t <= 10^4 ) -- the number of testcases. The first line of each testcase contains a single integer n ( 1 <= n <= 2 cdot 10^5 ). The second line contains n integers a_1, a_2, ... , a_n ( -10^9 <= a_i <= 10^9 ). All a_i are distinct. The sum of n over all testcases doesn't exceed 2 cdot 10^5 . For each testcase, print a single integer -- the smallest number of operations it can take you to make all elements equal, after you choose integers a_{n+1} and x . In the first testcase, you can choose a_{n+1} = 4 , the array becomes [1, 2, 3, 4] . Then choose x = 1 and apply the operation 3 times to the first element, 2 times to the second element, 1 time to the third element and 0 times to the fourth element. In the second testcase, you can choose a_{n+1} = 13, x = 4 . In the third testcase, you can choose a_{n+1} = 9, x = 1 . Then apply the operation once to a_{n+1} . "...