#arc128c. [arc128_c]Max Dot
[arc128_c]Max Dot
Problem Statement
Given are integers , , , and a sequence of integers .
Consider making a sequence of non-negative real numbers satisfying all of the following conditions:
- $0 \\leq x_1 \\leq x_2 \\leq \\cdots \\leq x_N \\leq M$,
- .
Now, let us define the score of as . Find the maximum possible score of .
Constraints
- All values in input are integers.
Input
Input is given from Standard Input in the following format:
Constraints
Print the answer. Your output will be considered correct if its absolute or relative error is at most .
Sample Input 1
3 2 3
1 2 3
Sample Output 1
8.00000000000000000000
The optimal choice is .
Sample Input 2
3 3 2
5 1 1
Sample Output 2
4.66666666666666666667
The optimal choice is .
Sample Input 3
10 234567 1000000
353239 53676 45485 617014 886590 423581 172670 928532 312338 981241
Sample Output 3
676780145098.25000000000000000000