AGGRCOW  Aggressive cows
Farmer John has built a new long barn, with N (2 <= N <= 100,000)
stalls. The stalls are located along a straight line at positions
x1,...,xN (0 <= xi <= 1,000,000,000).
His C (2 <= C <= N) cows don't like this barn layout and become
aggressive towards each other once put into a stall. To prevent the
cows from hurting each other, FJ wants to assign the cows to the
stalls, such that the minimum distance between any two of them is
as large as possible. What is the largest minimum distance?
Input
t – the number of test cases, then t test cases follows.
* Line 1: Two spaceseparated integers: N and C
* Lines 2..N+1: Line i+1 contains an integer stall location, xi
Output
For each test case output one integer: the largest minimum distance.
Example
Input:
1 5 3 1 2 8 4 9
Output:
3
Output details:
FJ can put his 3 cows in the stalls at positions 1, 4 and 8,
resulting in
a minimum distance of 3.
hide comments
rv6023:
20200830 19:00:10
use this testcase:


hafiz_:
20200825 19:03:19
@kishor_e it is also true choosing 1,4,9 but the answer will remain same. 

dharan1011:
20200822 22:30:11
AC 0.04 in on go!! 

nakli_c0der:
20200811 05:31:14
Those who got AC, kindly check this test case...


mr_cchef:
20200804 14:51:00
AC in 0.03 seconds. 

karlo_2107:
20200801 15:47:56
AC 0.08!!! You need to binary search minimal distance between cows and after that check it out! Easy :) 

gnomegeek:
20200728 15:39:51
Great Question to feel and fell for BS (Binary Search) xD 

kishor_e:
20200728 12:09:05
why not choose 1,4,9? 

danny_132:
20200726 10:49:44
Really good problem on Binary search . This basically involves the concept of binary search on answer where we decide which side will give better answer(left or right if some condition satisfies) after finding the mid. Watch video on Binary search by ERRICHTO he has explained the concept really well using the largest >=x problem in his video. 

adarshraj365_:
20200726 06:06:37
AC in 0.07 sec !!

Added by:  Roman Sol 
Date:  20050216 
Time limit:  2s 
Source limit:  10000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All 
Resource:  USACO February 2005 Gold Division 