SOLVE
LATER
Given $$2*N$$ pebbles of $$N$$ different colors, where there exists exactly $$2$$ pebbles of each color, you need to arrange these pebbles in some order on a table. You may consider the table as an infinite 2D plane.
The pebbles need to be placed under some restrictions :
In short consider you place a pebble of color $$i$$ at co-ordinate $$(X,Y)$$. Here, it is necessary that $$(i=X)$$ , $$(i!=Y)$$ there exist some other pebbles of color equal to $$Y$$.
Now, you need to enclose this arrangement within a boundary , made by a ribbon. Considering that each unit of the ribbon costs $$M$$, you need to find the minimum cost in order to make a boundary which encloses any possible arrangement of the pebbles. The ribbon is sold only in units (not in further fractions).
Input Format:
First line consists of an integer $$T$$ denoting the number of test cases. The First line of each test case consists of two space separated integers denoting $$N$$ and $$M$$.
The next line consists of $$N$$ space separated integers, where the $$i^{th}$$ integer is $$A[i]$$, and denotes that we have been given exactly $$2$$ pebbles of color equal to $$A[i]$$. It is guaranteed that $$A[i]!=A[j]$$, if $$i!=j$$
Output Format:
Print the minimum cost as asked in the problem in a separate line for each test case.
Constraints:
$$ 1 \le T \le 50 $$
$$ 3 \le N \le 10^5 $$
$$ 1 \le M \le 10^5 $$
$$ 1 \le A[i] \le 10^6 $$ ; where $$1 \le i \le N$$
An arrangement can be :
Pebbles of color 1: (1,2) , (1,3)
Pebbles of color 2: (2,1) , (2,3)
Pebbles of color 3: (3,1) , (3,2)
The length of ribbon required is= 6.828427125
The cost of ribbon is = 7*5=35 as we have to buy ribbon in units.
This arrangement's boundary covers all possible arrangements.