Quiz 49: Find the subset with minimum- Max(subset)-Min(subset)

Problem:

Given T number, you have to select N numbers such that Max(Selection)-Min(Selection) is minimum. Print Max(Selection)-Min(Selection)
ex: if T=3 and N=2 and numbers are 1,2,4 , then selection can be (1,2) or(2,4) or (1,4).
max(1,2)-min(1,2)=2-1=1
max(2,4)-min(2,4)=4-2=2
max(1,4)-min(1,4)=4-1=3
Clearly 1 is minimum, so output should be 1.

Input Format: 

Total number T
Subset number N
next T lines having numbers

Output Format: 
Max(Selection)-Min(Selection)

Constraints: 
none

Sample Input

7
3
2
6
10
12
4
11
16

Sample Output:
2

Explanations:
We have to select 3 numbers from 7 numbers- 2,6,10,12,4,11,16.
We should select 10,11,12. Max(10,11,12)=12. Min(10,11,12)=10. Diff=2. All other possible combinations have difference more than 2.

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Solution:

chomp($t=<STDIN>);
chomp($n=<STDIN>);
for($i=0;$i<$t;$i++)
{
chomp($tmp=<STDIN>);
push(@arr,$tmp);
}
@arr=sort{$a<=>$b}@arr;
$ans=$arr[$t-1];
$up=$t-$n;
for($i=0;$i<=$up;$i++)
{
$t=$arr[$i+$n-1]-$arr[$i];
if($t<$ans){$ans=$t;}
}
print $ans;

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Tips:

Sort all numbers and then calculate for all possible orders using sorted list