**Perfect hashing... Experts-Exchange**

Is there a hash function that satisfies all the following properties: 1. It is 1 to 1 (no collisions). 2. It can take any size input. 3. For any input, and some desired set of characters, there exists a third set characters that can be appended to the input so that the output starts with the desired characters.... A good supplemental hash function is a bit more complex, but this one is good enough for my use case (it doesn't need to be perfect). number-theory modular-arithmetic computer-science hash-function share cite improve this question

**A Dynamic Perfect Hash Function Defined by an Extended**

I have a set of C++ functions. I want to map this functions in an hash table, something like: unordered_map9/09/2014Â Â· A few days ago, a friend asked me how to write, if even possible, a hash function that had no collisions. Of course, itâ€™s relatively easy to get a reasonably good hash function that will give the expected amount of collisions (especially when used as usual, modulo the size of the table)., SomethingElse>, where SomethingElse is not relevant for this question....

**How to Create A Hash Table Project in C++ Part 3**

A good supplemental hash function is a bit more complex, but this one is good enough for my use case (it doesn't need to be perfect). number-theory modular-arithmetic computer-science hash-function share cite improve this question how to find who my gas supplier is Introduction to gperf. GNU gperf is a perfect hash function generator. For a given list of strings, it produces a hash function and hash table, in form of C or C++ code, for looking up a value depending on the input string.. How to find the perfect foundation for your face

## How To Get A Perfect Hash Function

### Perfect Hash Function Generator GNU

- hashtable perfect hash function - Stack Overflow
- Perfect (or almost perfect) Hash function for n bit
- How to Create A Hash Table Project in C++ Part 3
- Hash Functions College of Computer and Information Science

## How To Get A Perfect Hash Function

### By perfect hash function I mean that there is no chance of collision. Basically I am reading the signatures of multiple tables from a file (e.g. id, name, address). Different tables might have common attributes (e.g. name), but on different positions (i.e. columns).

- It maintains an array of SequentialSearchST objects and implements get() and put() by computing a hash function to choose which SequentialSearchST can contain the key and then using get() and put() from SequentialSearchST to complete either job.
- 22/03/2016Â Â· To be clear, "perfect hash function" is a well-defined concept, and there absolutely are perfect hash functions. I think what biject.bwts means to say is that there are no perfect hash functions for infinite sets. PHFs require knowledge of the entire key space when they are generated, which greatly limits their applications.
- Given a collection of items, a hash function that maps each item into a unique slot is referred to as a perfect hash function. If we know the items and the collection will never change, then it is possible to construct a perfect hash function (refer to the exercises for more about perfect hash functions). Unfortunately, given an arbitrary collection of items, there is no systematic way to
- This is the idea of perfect hashing - to use hash table of second level for elements that have the same hash value (in average, if I use good hash function it won't be greater than 2 elements with the same hash). In this way I can check if an element in the table in O(1) time. But if I use linked list for collisions in the cells it won't be O(1).

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