Given a dictionary of words, where will a newly coined word be most likely
We are given k, the length of the new word, and dictionary, a String of words in ascending alphabetical order. Suppose that the new word is equally likely to be any k-letter word that is not already in the dictionary. Return the most likely 0-based index for the new word. If there is more than one most likely index, return -1.
|-||dictionary will contain between 1 and 50 elements, inclusive.|
|-||Each element of dictionary will contain between 1 and 50 characters, inclusive.|
|-||Each character in each element of dictionary will be a lowercase letter ('a'-'z').|
|-||The elements of dictionary will be distinct and in ascending alphabetical order.|
|-||k will be between 1 and 10, inclusive.|
|-||There will be at least one k-letter word that is not in dictionary.|