SP7566 IITD5 - Expected Cycle Sums
Description
We are given a sequence S of N distinct integers. Denote by S\[i\] as ith element of S.
Hardik picks up a random permutation of S , breaks it into product of disjoint cycles & looks at cycle containing S\[i\].He notes down the sum of all element of this cycle. Call the expected value of this sum as cycleSum\[i\]. Your task is to find the minimum value amongst all cycleSums.
Assume all permutations of these N numbers are equally likely.
**Input Format :**
First line contains an integer T which denotes the number of test cases. Then follow description of T test scenarios. Each test scenario takes 2 lines. First line contains a single integer N, the size of S. Then follows second line containing N elements of S.
**Output Format :**
Print answer for each test case , rounded to exactly one decimal place , in one line each.
**Sample Input :**
2
1
1
2
1 2
**Sample Output:**
1.0
2.0
**Note:** Notion of cycles for any sequence is defined by using index in the sequence (1-N).
**Explaination for sample output** :
In first case only possible permutation is (1) So answer is trivially 1.0
In second case possible permutations are (1)(2) & (12). As both of these are equally likely, cycleSum\[1\] = 1/2 \* 1 + 1/2 \* (1+2) = 2.0
And cycleSum\[2\] = 1/2 \* 2 + 1/2 \* (1+2) = 2.5. Smaller of these is 2.0 , hence the answer.
**Constraints :**
1
Input Format
N/A
Output Format
N/A