Map Sum Pairs

Statement

Design a data structure that supports the following operations:

1. Insert a key-value pair:

   1. Each key is a string, and each value is an integer.

   2. If the key already exists, update its value to (overriding the previous value).

2. Return the prefix sum:

   1. Given a string, prefix, return the total sum of all values associated with keys that start with this prefix.

To accomplish this, implement a class MapSum:

• Constructor: Initializes the object.

• void insert (String key, int val): ...