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
thakur_2312:
20201010 07:10:24
Nice question.....Got an AC...wonderful question on binary search 

omkarg_1417:
20201008 14:29:33
Finally got an AC after a lot of tries. Well everyone is saying it's combination of greedy and binary search, I'll give a hint, start from 0 and keep end as last value  first value 

coder582:
20201006 19:01:38
Just keep in mind that Binary Search is applied on a SOLUTION SPACE. 

mohit_me2021:
20200921 08:39:44
Can anybody guide me to the editorials of spoj problems


code_999:
20200909 19:52:18
if consider the position is 2 4 8 12, we can place at 4 8 and 12 with maxmin distance 4 for(C=3) or one sol is also 2 8 12. So even if we do not select the first pos and we have the answer, it is sure that selecting first pos will also always give the answer. Hence every solution is accepting that we are putting the first cow in the first position. Last edit: 20200909 19:53:48 

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. 
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 