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
black_spider1: 2020-06-03 15:33:14

what are the contraints of t ? they should clearly mention that in question.

pradeep_7: 2020-05-22 05:25:39

Test Cases :
1
10 4
1 2 3 4 5 6 7 8 9 10

O/P - 3

1,4,7,10 --- 4 Cows Can Place Here

puthal_101: 2020-05-21 20:29:34

got WA. i need more test case as i am getting 3 for given input

amar_shukla1: 2020-05-19 18:18:48

The best question to learn binary search!!!

subhajit_1999: 2020-05-18 22:40:51

good problem

saddy_2001: 2020-05-08 22:50:35

this is a nice question for implementation of binary search !

shikhar2402_: 2020-05-08 12:19:19

why not choose 1,4,9

sacsachin: 2020-05-04 18:03:17

Finally AC after 6 WA.

rohit_mahale: 2020-05-02 12:02:12

good problem...if you dont able to come up with the approach just read some tutorial or watch some explaination videos instead just jump onto the actual solution.

"binary search with greedy technique to find out that this minimum range could be the answer or not."

" i have read this problem a year ago but did not manage to solve that time and tried it now and got AC in 1 go "

Last edit: 2020-05-02 12:03:29
chikku: 2020-04-29 13:08:23

tf does this question mean?


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