Problem Statement

Two words are called isomorphic if the letters in one word can be remapped to get the second word. Remapping a letter means replacing all occurrences of it with another letter. The ordering of the letters remains unchanged. No two letters may map to the same letter, but a letter may map to itself.

For example, the words "abca" and "zbxz" are isomorphic because we can map 'a' to 'z', 'b' to 'b' and 'c' to 'x'.

Given a String[] words, return how many (unordered) pairs of words are isomorphic.

Definition

 Class: IsomorphicWords Method: countPairs Parameters: String[] Returns: int Method signature: int countPairs(String[] words) (be sure your method is public)

Constraints

-words will contain between 2 and 50 elements, inclusive.
-Each element of words will contain between 1 and 50 lowercase letters ('a'-'z'), inclusive.
-All elements of words will have the same length.
-There will be no duplicates in words.

Examples

0)

 `{"abca", "zbxz", "opqr"}`
`Returns: 1`
 "abca" and "zbxz" are isomorphic, but none of the two is isomorphic with "opqr".
1)

 `{"aa", "ab", "bb", "cc", "cd"}`
`Returns: 4`
 The four isomorphic pairs are {"aa", "bb"}, {"aa", "cc"}, {"bb", "cc"} and {"ab", "cd"}.
2)

 ```{ "cacccdaabc", "cdcccaddbc", "dcdddbccad", "bdbbbaddcb", "bdbcadbbdc", "abaadcbbda", "babcdabbac", "cacdbaccad", "dcddabccad", "cacccbaadb", "bbcdcbcbdd", "bcbadcbbca" }```
`Returns: 13`

Problem url:

http://www.topcoder.com/stat?c=problem_statement&pm=8175

Problem stats url:

http://www.topcoder.com/tc?module=ProblemDetail&rd=11125&pm=8175

lovro

Testers:

PabloGilberto , Olexiy , ivan_metelsky

Problem categories:

Simple Search, Iteration, String Manipulation