Implement a system that:

• Records a rating for a given agent on a given date.
• Returns all agents with their overall average ratings, sorted from highest to lowest.
• Returns best agents for a given month (YYYY-MM) based on their average ratings.

Constraints

• rating is an integer between 1 and 5.
• agentName is a non-empty, case-sensitive string.
• date is in YYYY-MM-DD format; month is YYYY-MM.
• System should handle thousands of agents and millions of ratings efficiently.
• Average ratings must be rounded to single decimal point,
  4.33 becomes 4.3, 4.35 or 4.37 becomes 4.4

Methods

rateAgent

void rateAgent(String agentName, int rating, String date)

• agentName: non-blank agent identifier.
• rating: integer in [1, 5].
• date: rating date in "YYYY-MM-DD" format.
• Each call records a single rating event for that agent on that date.

getAverageRatings

List<String> getAverageRatings()

• Returns overall average rating per agent.
• Each entry is in the format "agentName,averageRating" (e.g., "Bob,4.5").
• Sorted in descending order of averageRating.
• If two agents have the same average rating, order them by agent name in lexicographically ascending order.

getBestAgentsByMonth

List<String> getBestAgentsByMonth(String month)

• month: month string in "YYYY-MM" format (e.g., "2025-03").
• Considers only ratings whose date falls in the given month.
• Each entry is in the format "agentName,averageRating".
• Sorted in descending order of averageRating for that month.
• If two agents have the same average rating, order them by agent name in lexicographically ascending order.

Examples

Example 1 – Overall Average Ratings

Input:

rateAgent("Alice", 5, "2025-03-12")
rateAgent("Bob", 4, "2025-03-13")
rateAgent("Alice", 3, "2025-03-15")
rateAgent("Bob", 5, "2025-03-18")
getAverageRatings()

Output:

[
  "Bob,4.5",
  "Alice,4.0"
]

Explanation:
Bob → (4 + 5) / 2 = 4.5
Alice → (5 + 3) / 2 = 4.0
Sorted from highest to lowest average rating.

Example 2 – Best Agents by Month

Input:

rateAgent("Alice", 5, "2025-02-02")
rateAgent("Bob", 3, "2025-02-05")
rateAgent("Charlie", 4, "2025-02-10")
rateAgent("Bob", 5, "2025-03-12")
rateAgent("Alice", 2, "2025-03-15")
getBestAgentsByMonth("2025-02")

Output:

[
  "Alice,5.0",
  "Charlie,4.0",
  "Bob,3.0"
]

Explanation:
Only ratings with dates in February 2025 are considered.
Agents are ordered from highest to lowest average rating for that month.