Part $2$: Unordered Map $(40\%)-$ similar to maps, unordered maps are associative containers that store key$-$value pairs.

However, the unordered map is implemented using a hash table instead of a tree, which allows for $O(1)$ find and remove. The

drawback is that the elements are no longer ordered, so it does not support find Min or find Max, and cannot produce a sorted

output using iterator traversal.

Implement an unordered map ADI using a hash table $($separate chaining or double hashing$)$ as the underlying data structure.

You may use std libraries for the linked list $($separate chaining$)$ and hash functions. If the hash table becomes overloaded $(>$

$0\mathrm{.}5)$ it should allocate more space and rehash all the existing elements. Don't forget the big $5!$

mapped$\_$types operator$[]($const key$\_$types k$)$;

if $k$ matches the key of an element in the container, the function returns a reference to its mapped value. If $k$

does not match the key of any element, insert a new key$-$value pair with key $k$ and value constructed using

mapped$\_$type default constructor and return a reference to the new mapped$\_$type object.

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