Count Distinct Passwords

Problem Overview

• Compute the variability of a password as the count of distinct strings formed by reversing any one substring of the given password.
• Input: a lowercase English string (length 1 to 1e5); Output: a long integer count.
• Context: password health assessment and security in real-world systems.
• Source: Amazon interviews; a common coding interview problem and interview question.
• Implement the function countDistinctPasswords(password) to return the total distinct results.