Score : 500 points
You have a string A = A_1 A_2 ... A_n consisting of lowercase English letters.
You can choose any two indices i and j such that 1 \leq i \leq j \leq n and reverse substring A_i A_{i+1} ... A_j.
You can perform this operation at most once.
How many different strings can you obtain?
Input is given from Standard Input in the following format:
A
Print the number of different strings you can obtain by reversing any substring in A at most once.
aatt
5
You can obtain aatt
(don't do anything), atat
(reverse A[2..3]), atta
(reverse A[2..4]), ttaa
(reverse A[1..4]) and taat
(reverse A[1..3]).
xxxxxxxxxx
1
Whatever substring you reverse, you'll always get xxxxxxxxxx
.
abracadabra
44