Question 1 (hash) – is it even remotely possible to reverse engineer the hash function when given lots of output?
For example if the underlying hash function is something simple like
tolower(word) % N, and we are given 100,000+ words from the dictionary and all their respective hash values, will the computer eventually be smart enough to connect the dots and know that we are using the ASCII table and a modulo?
Question 2 (load) – the conventional way to insert a node to an existing linked list, according to the pset5 walkthrough, is to link the new node to the first element and then set the header to the new node, so the linked list (in the example of an alphabetically sorted document) will look like HE -> HB -> HA etc.
Can we do it the other way around so that you first look through the existing linked list, and find the only node that has the NULL pointer, and set it to link to the new node, so the list will look like HA -> HB -> HE. I can’t think of why in theory this might not be working, and would love to know a). why CS50 seems to avoid this seemingly more intuitive method on purpose? b). what’re the pros and cons comparing to the conventional way?
The reason I’m asking this question is that it seems that BTC blockchain is done and verified in the HA -> HB -> HE order, and it seems that always having to break/reconnect the header when a new node is introduced is intuitively not a very secured practice.
Question 3 (unload) – let’s say someone did all the coding work and it’s our job to make sure the unload is thorough, but we can’t access to their code and can only write our own code to check (but not allowed to use things like valgrind), let’s say if they freed all the memory except one node in the middle of a linked list (like a space garbage floating in the void without any linkage).
Is it even possible to use a while loop again to go through the now almost perfectly cleaned hash table again and identify that particular node?