An underwriting system receives customer events one at a time. Implement DistinctPIIValuesCounter to track the number of distinct PII (Personally Identifiable Information) values found across all underwriting events processed so far.
Each event is represented by a String[] with exactly five elements: [eventType, address, phone, email, ssn]. The address, phone, email, and ssn elements are PII fields.
Implement the DistinctPIIValuesCounter class:
DistinctPIIValuesCounter() initializes the counter with no recorded PII values.