Struct BijectiveMap 

pub struct BijectiveMap<KT, VT, const CAP: usize = 16> { /* private fields */ }

This is your bijective map struct

Implementations

impl<KT: Hash + Eq, VT: Hash + Eq, const CAP: usize> BijectiveMap<KT, VT, CAP>

pub fn new() -> Self

creates a new BijectiveMap with default initial capacity:

pub fn get_by_key(&mut self, key: &KT) -> Option<&VT>

Returns a immutable reference to the value corresponding to the given key, if it exists. Note that there can’t be a Option<&mut T> version of this method because changing the value will require adjusting other associations in the map. This function has been completed and you can consult its source as hint.

impl<KT: Hash + Eq, VT: Hash + Eq, const CAP: usize> BijectiveMap<KT, VT, CAP>

Place all your code in another impl block, and fully implement the methods BijectiveMap::get_by_val, BijectiveMap::take_by_key, BijectiveMap::take_by_val, and BijectiveMap::set.

pub fn len(&self) -> usize

Returns number of key-value pairs in this map. This one’s too easy so I just did it for you again. I will give away more stuff if you come to me for help …

pub fn get_by_val(&mut self, val: &VT) -> Option<&KT>

This is the first method you need to implement. Returns an immutable reference to the key associated with the given value, if it exists. The dummy provided here just returns None and you need to rewrite it appropriately.

pub fn take_by_key(&mut self, key: &KT) -> Option<(KT, VT)>

This is another method you need to implement. Removes key-value pair from map by searching for it by key. Returns the key and value if found. Note that this function is “take” and not “get” because it moves the actual key and value out of the map. It doesn’t return references. Sometimes you may need to convert an Option<T> to an Option<&T>. To do that, given such an Option<T> opt, use the expression opt.as_ref().

The dummy implemenetation provided here just returns None

pub fn take_by_val(&mut self, val: &VT) -> Option<(KT, VT)>

Dummies always return None. Are you a dummy?

pub fn set(&mut self, key: KT, val: VT) -> Option<(KT, VT)>

Change or add key-val pair, return a pair to represent information that was deleted. Note that the returned key,value, if they exist, may indicate a different key or value that existed in the map before the change (see “daynum” example that you should replicate in main). Replace the dummy implementation.