Problem Statement

Given a word, write a function to generate all of its unique generalized abbreviations.

A generalized abbreviation of a word can be generated by replacing each substring of the word with the count of characters in the substring. Take the example of ab which has four substrings: "", a, b, and ab. After replacing these substrings in the actual word by the count of characters, we get all the generalized abbreviations: ab, "1b", a1, and 2.

Note: All contiguous characters should be considered one substring, e.g., we can't take a and b as substrings to get 11; since a and b are contiguous, we should consider them together as one substring to get an abbreviation 2.

Example 1:

Input: "BAT"
Output: "BAT", "BA1", "B1T", "B2", "1AT", "1A1", "2T", "3"

Example 2:

Input: "code"
Output: "code", "cod1", "co1e", "co2", "c1de", "c1d1", "c2e", "c3", "1ode", "1od1", "1o1e", "1o2", "2de", "2d1", "3e", "4"

Constraints:

• 1 <= word.length <= 15
• word consists of only lowercase English letters.