Asked by Google

Question

Implement a key value store, where keys and values are integers, with the following methods:

• update(key, vl): updates the value at key to val, or sets it if doesn't exist

• get(key): returns the value with key, or None if no such value exists

• max_key(val): returns the largest key with value val, or None if no key with that value exists

For example, if we ran the following calls:

kv.update(1, 1)
kv.update(2, 1)

And then called kv.max_key(1), it should return 2, since it's the largest key with value 1.