Check Permutation: Given two strings, write a method to decide if one is a permutation of the other.

I’m working through algorithm exercises with a group of people, and there was a lot of confusion about what permutation means, and how it differs from anagrams and palindromes.

So, to clarify:

A permutation is one of several possible variations, in which a set of things (like numbers, characters or items in an array) can be ordered or arranged. A permutation of characters does not have to have meaning.

Example: Given the string abcd, the permutations are abcd, abdc, acbd, acdb, adbc, adcb, bacd, badc, bcad, bcda, bdac, bdca, cabd, cadb, cbad, cbda, cdab, cdba, dabc, dacb, dbac, dbca, dcab and dcba

An anagram is a word, phrase, or name formed by rearranging the characters of a string. An anagram must have meaning, it can’t just be gibberish.

Example: These words are anagrams of carets: caters, caster, crates, reacts, recast, traces

A palindrome is a word, phrase, or sequence that reads the same backward as forward. A palindrome must have meaning, it can’t just be gibberish.

Example: Civic, level, madam, mom and noon are all palindromes.

All palindromes and anagrams are permutations, but not all permutations are either anagrams or palindromes.