A bucket is simply a fast-access location (like an array index) that is the the result of the hash function. The idea with hashing is to turn a complex input value into a different value which can be used to rapidly extract or store data. Consider the following hash function for mapping people’s names into … Read more
It’s impossible to know in advance how many collisions you will get with your hash function, as well as things like needing to resize. This can add an element of unpredictability to the performance of a hash table, making it not true O(1). However, virtually all hash table implementations offer O(1) on the vast, vast, … Read more
First you shoud maybe read this article. When you use lists and you are looking for a special item you normally have to iterate over the complete list. This is very expensive when you have large lists. A hashtable can be a lot faster, under best circumstances you will get the item you are looking … Read more