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
tumasterlli: 2020-06-28 20:17:03

AC in One Go!!!

kumar_anubhav: 2020-06-23 23:09:56

AC in 3rd attempt, was confused whether 0 will answer for maximizing the minimum distance :))

ashishk47: 2020-06-16 07:52:44

My first AC in one Go !! :')
Read about Discreet Binary Search before you attempt this, this concept blew my mind.
https://www.topcoder.com/community/competitive-programming/tutorials/binary-search/

sujay008: 2020-06-15 16:33:20

I have been stuck on this question for ages, finally did it!! for those who are still stuck can go check out allocation of pages problem, the question is different but the concept is same. don't leave the question coz this is a great question for binary question.

ishanarya0: 2020-06-11 12:20:32

input:
6
10 3
1 2 9 8 4 4 8 9 2 1
5 3
1 2 8 4 9
20 3
9 8 7 10 6 5 4 3 2 1 19 18 17 16 15 14 13 12 11 20
3 3
0 1000000000 500000000
20 4
9 8 7 10 6 5 4 3 2 1 19 18 17 16 15 14 13 12 11 20
20 5
9 8 7 10 6 5 4 3 2 1 19 18 17 16 15 14 13 12 11 20
output:
3
3
9
500000000
6
4

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


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