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
kapilgm:
20180327 08:49:43
AC in 12th go!!


yaswanth desu:
20180321 15:19:32
Hello Everyone,


amitboss:
20180316 18:54:10
good problem , 100th on spoj 

prasoon_07:
20180314 03:51:34
topcoder is awesome :) 

kkislay20:
20180312 15:14:05
This was one of the finest problems I had come across on spoj. It gave me more insights for binary search, topcoder and quora helped a lot. 

zephyr_96:
20180226 14:23:56
@shobit1998, It works with high=mid1 too. Maybe there is some fault in your implementation. 

shobhit1998:
20180214 16:32:31
in else part of binary search why does high = mid and high = mid1 make a difference in answer 

rob_in_1:
20180122 12:43:07
Last edit: 20180228 19:52:33 

garrykevin:
20180109 13:10:51
For those who are wondering about , why the cows should be placed in positions 1 4 8. Why couldnt it be 1 4 9 since it indicates largest distance as possible.


kkarthikeyan98:
20180108 17:29:49
In the example test case, why the cows should be placed in positions 1 4 8. Why couldnt it be 1 4 9 since it indicates largest distance as possible. Please help! 
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 