hashtable

When we put a key instance say "key" and a Value instance say "value" in a HashMap class using put() method , what does the HashMap class do internally . How does it retrieve the value back when we say hashMap.get(key) ? Edit : I do not want details here , basically trying to understand the bigger picture and the role of equals() and hashcode() method in put() and get() operations. amicngh If you talk about higher picture it is just like below.Here i refer item as a key of Map While Putting items. Calculate hashcode of key If basket with that hashcode is present then use the equals method on

I'm currently implementing a hash table in C++ and I'm trying to make a hash function for floats... I was going to treat floats as integers by padding the decimal numbers, but then I realized that I would probably reach the overflow with big numbers... Is there a good way to hash floats? You don't have to give me the function directly, but I'd like to see/understand different concepts... Notes: I don't need it to be really fast, just evenly distributed if possible. I've read that floats should not be hashed because of the speed of computation, can someone confirm/explain this and give me other

What's the big O for JavaScript's array access when used as a hash? For example, var x= []; for(var i=0; i<100000; i++){ x[i.toString()+'a'] = 123; // using string to illustrate x[alpha] } alert(x['9999a']); // linear search? One can hope JS engines will not use a linear search internally O(n), but is this for sure? Accessing object properties and array elements in JavaScript is syntacticly assumed to be done in constant time : O(1). Performance characteristics are not guaranteed in the ECMAScript specification, but all the modern JavaScript engines retrieve object properties in constant time.

Recently, I attended an interview and faced a good question regarding hash collisions. Question : Given a list of strings, print out the anagrams together. Example : i/p : {act, god, animal, dog, cat} o/p : act, cat, dog, god I want to create hashmap and put the word as key and value as list of anagrams To avoid collision, I want to generate unique hash code for anagrams instead of sorting and using the sorted word as key. I am looking for hash algorithm which take care of collision other than using chaining. I want algorithm to generate same hash code for both act and cat... so that it will

I have a few questions on a data-structure called a hash table (also know as associative array) and how it is implemented in C. How do you make a hash table in C? What is a hashtable and how do you implement it? Why would I want to use a hash table rather than an array? NOTE: I know this is a really broad question which will require a large answer but, I made this because I had some people asking me what it all was. so I put it on here to fully explain it and help anyone else out. Prerequisites For this answer I'm going to assume you know how to use pointers, structs, and have a basic

I'm using Swift 2 and using WeakContainer as a way to store a set of weak objects, much like NSHashTable.weakObjectsHashTable() struct WeakContainer<T: AnyObject> { weak var value: T? } public protocol MyDelegate : AnyObject { } Then in my ViewController, I declare public var delegates = [WeakContainer<MyDelegate>] But it is error Using MyDelegate as a concrete type conforming to protocol AnyObject is not supported I see that the error is that WeakContainer has value member declared as weak , so T is expected to be object. But I also declare MyDelegate as AnyObject , too. How to get around