CRUD Operations for Key-Value Store with Advanced Search

Implement a Key-Value store supporting basic CRUD operations with advanced key searching capabilities. The system should support the following operations: get(key): Retrieve the value associated with the key. set(key, value): Set the key to be associated with the value. update(key, value): Update the value associated with the key to the new value. delete(key): Remove the key-value pair from the store. prefixSearch(prefix): Return all values of keys starting with the prefix. containSearch(substring): Return values of keys containing the substring or null if the key does not exist. Please implement these operations and provide relevant test cases. Example set("abc", 1) set("abcd", 2) prefixSearch("ab") // returns [1, 2] containSearch("ab") // returns null containSearch("abc") // returns 1 Constraints The number of keys and values ranges from [1, 10^5]. The length of the string key ranges from [1, 100]. The time complexity of any operation is O(N), where N is the size of the key set. Example Input set abc 1 set abcd 2 prefixSearch ab containSearch ab containSearch abc