Palindromes | Topcoder Archive

Problem Statement

A palindrome is a string of length 1 (one) or greater that is the same both forwards and backwards. Examples are "AGA", "HANNAH", and "RACECAR".

Given a String word, calculate the number of unique palindromes that can be made out of the characters in word, using each character exactly once (see examples).

Definition

Class:: Palindromes
Method:: count
Parameters:: String
Returns:: int
Method signature:: int count(String word)
(be sure your method is public)

Constraints

word has length between 1 and 17, inclusive.
word will contain only capital letters ('A'-'Z').

Examples

```
"ABB"
```
```
Returns: 1
```
The only palindrome is "BAB".
```
"ABBA"
```
```
Returns: 2
```
The two legal palindromes are "ABBA" and "BAAB".
```
"AMBSEAMBS"
```
```
Returns: 24
```
```
"ABC"
```
```
Returns: 0
```
```
"AABBCCDDEEFFGGHHI"
```
```
Returns: 40320
```

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