PROGRAMMING:Mince pie
Keven now has a lot of pies, different tastes and sizes. His friends all want a piece of pie. Note that it should be a piece of pie, not a few small pies, because it looks very messy.
His friends are annoying, and if one of them gets a bigger share than the others, they start complaining. So * * they should all get the same size (but not necessarily the same shape) piece of pie * *, even if it causes some pies to be cut. Of course, I also want a piece of pie for myself, which should be the same size.
What is the maximum area we can get? All pies are round, regardless of height, but the radius of the pie is not equal.
**(everyone's pie shape is not necessarily round, as long as the pie is a whole piece and the area of everyone's pie is equal.)**
###Input format:
The first line is a positive integer: the number of test cases. Then, for each test case:
The first line contains two integers n and F, where 1 ≤ N and f ≤ 10000 represent the number of pies and friends.
A row of N integers RI, 1 ≤ RI ≤ 10000: the radius of the pie.
###Output format:
For each test case, my friends and I can get the maximum area of a pie. The answer should be a floating-point number with four decimal places.
###Input example:
Here is a set of inputs. For example:
```in
three
3 3
4 3 3
1 24
five
10 5
1 4 2 3 4 5 6 5 4 2
```
###Output example:
The corresponding output is given here. For example:
```out
twenty-five point one three two seven
three point one four one six
fifty point two six five five
```
###Tips
$$PI = acos(-1.0)$$
The first group of cases: there are four people in total, and the area of the cake is respectively $$16pi $$, $$9pi $$, $$9pi $$, so each person can get a cake with an area of $$8pi $$. Why can't the answer be $$34pi / 4 $? Because this will cause some friends to get two pieces of cake, so the answer is illegal< br>
answer：If there is no answer, please comment
His friends are annoying, and if one of them gets a bigger share than the others, they start complaining. So * * they should all get the same size (but not necessarily the same shape) piece of pie * *, even if it causes some pies to be cut. Of course, I also want a piece of pie for myself, which should be the same size.
What is the maximum area we can get? All pies are round, regardless of height, but the radius of the pie is not equal.
**(everyone's pie shape is not necessarily round, as long as the pie is a whole piece and the area of everyone's pie is equal.)**
###Input format:
The first line is a positive integer: the number of test cases. Then, for each test case:
The first line contains two integers n and F, where 1 ≤ N and f ≤ 10000 represent the number of pies and friends.
A row of N integers RI, 1 ≤ RI ≤ 10000: the radius of the pie.
###Output format:
For each test case, my friends and I can get the maximum area of a pie. The answer should be a floating-point number with four decimal places.
###Input example:
Here is a set of inputs. For example:
```in
three
3 3
4 3 3
1 24
five
10 5
1 4 2 3 4 5 6 5 4 2
```
###Output example:
The corresponding output is given here. For example:
```out
twenty-five point one three two seven
three point one four one six
fifty point two six five five
```
###Tips
$$PI = acos(-1.0)$$
The first group of cases: there are four people in total, and the area of the cake is respectively $$16pi $$, $$9pi $$, $$9pi $$, so each person can get a cake with an area of $$8pi $$. Why can't the answer be $$34pi / 4 $? Because this will cause some friends to get two pieces of cake, so the answer is illegal< br>
answer：If there is no answer, please comment