Single-Rule Ad Filter

Problem Description

When a user watches content, the system needs to filter an ad pool to find ads that match a single rule with an operator. Implement a lightweight filter that supports this functionality.

Data Model

Ad

• id: String
• targetLocations: Set<String> (e.g., { "CA", "TX" } )
• age: int (intended viewer age for the ad)

Rule

• targetLocations: Set<String> (optional)
• minAge: Integer (optional)
• maxAge: Integer (optional)
• operator: "AND" | "OR"

Matching Semantics

• Location match: If rule.targetLocations is present and non-empty, an ad matches the location constraint if rule.targetLocations ⊆ ad.targetLocations (i.e., the ad targets all locations required by the rule).
• Age match:
  • If rule.minAge is present, require ad.age >= rule.minAge.
  • If rule.maxAge is present, require ad.age <= rule.maxAge.
• Combine the (present) constraints using rule.operator:
  • AND: Ad must satisfy all present constraints.
  • OR: Ad must satisfy at least one present constraint.
• If a constraint is absent, ignore it.

Input / Output

• Input: List<Ad> ads, Rule rule
• Output: List<String> of matching ad.id values, preserving the original input order.

Example

Rule: minAge = 21, targetLocations = {"US"}, operator = AND

Ads:

• A: age=21, targetLocations={"US","CA"} → match
• B: age=13, targetLocations={"US"} → no (age)
• C: age=25, targetLocations={"CA"} → no (location)

Output: ["A"]

Constraints

• ads.length can be large; keep it efficient.
• Location strings may vary in case; clarify/handle consistently (e.g., normalize to upper-case) if needed.