Олимпиадный тренинг

Задача 30709. Cows - in the stall


There are stalls on the straight line, in which it is necessary to place the cows so that the minimum distance between the cows is as large as possible.
 
Input: 
- numbers N  are entered in the first line (\(2 < N < 10001\)) – number of stalls, and K  (\(1 < K < N \)) – number of cows;
- the second line contains N natural numbers in ascending order – stable coordinates (coordinates do not exceed \(10^9\)).
 
Output: print a single number – the largest possible distance allowed.
 
Examples
# Input Output
1
6 3
2 5 7 11 15 20
9