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.
|-||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.|