According to wiki: An anagram is a type of word play, the result of rearranging the letters of a word or phrase to produce a new word or phrase, using all the original letters exactly once. An example: elvis/lives, funeral/realfun.
In this kata, please write a method which will check if the provided two strings are anagrams. If any argument is null, return false. As input all unicode characters starting from \u0000 to \uFFFF are accepted. Letters size does matter i.e. Foo and oof are not anagrams in this case.
For more challenge try to solve that problem in O(n) complexity.