Group Messages by Sender

📝 Description

Group messages by sender in a dictionary.

Input Format

[ {"sender": "Alice", "message": "Hi"}, {"sender": "Alice", "message": "Hey"} ]

Output Format

{ "Alice": ["Hi", "Hey"] }

Constraints

Number of messages ≤ 10^5

🔍 Sample Input

[ {"sender": "Alice", "message": "Hi"}, {"sender": "Alice", "message": "Hey"} ]
            

✅ Sample Output

{ "Alice": ["Hi", "Hey"] }