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 space-separated 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
Shubham Aggarwal: 2017-11-20 22:18:05

I tested it on a lot of cases, it runs find, but here I'm getting NZEC in python

balakrishna21: 2017-11-19 06:43:57

could any one give any some more test cases for this "AGGRCOW - Aggressive cows
" problem

themast3r: 2017-11-01 16:59:04

Possibly the finest problem I solved on SPOJ.

Last edit: 2017-11-01 16:59:18
rebornplusplus: 2017-10-22 10:48:44

Nice problem ;)

jd_tc: 2017-10-20 09:30:44

Thank @grb_avatar for the link, it was really helpful :) :)

edujtm: 2017-10-20 04:50:22

Struggled a lot with this one, hard to define if the binary search is going to give you the result you want. TopCoder helped a lot.

arjun_agrawal: 2017-09-05 06:45:06

Thought this question in a backward manner. Try to search for the answer in a binary search fashion and check its feasibility

pkgleb: 2017-08-27 18:47:35

First, I found solution using Indexed priority queue, but after topcoder's article lecture the solution just show up :)

kspoj: 2017-08-24 20:29:26

Quora helped :)

iket0512: 2017-08-20 07:29:56

Last edit: 2017-08-20 07:30:22

Added by:Roman Sol
Date:2005-02-16
Time limit:2s
Source limit:10000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All
Resource:USACO February 2005 Gold Division