hash function

Data Structure-Hash FunctionHash search In the previous search algorithm, the time complexity is O (n) or O (2n). The efficiency depends on the number of "comparisons. Even if the search results of a table using the sort tree structure are different

In the computational theory, there is no hash function, only one-way function is said. The so-called one-way function, is a complex definition, you can see the computational theory or cryptography data. The "Human" language describes the one-way

Document directory 1. Direct addressing 2. Digital Analysis 3. China and France 4. Folding Method 5. Except the remaining remainder 6. Random Number Method 1. Open address Method 2. rehash 3. link address Method 4. Create a public

Defined:The hash function h takes the variable-length data block M as input, producing a fixed-length hash value h = h (m). Called M is the original image of H. Because H is a many-to-one mapping, there are multiple primitives for any given hash

Transfer from http://www.smatrix.org/bbs/simple/index.php?t5591.html//////////////////////////////////////////////////////////////////////////////Directory1. PHP hash function and its application2. Symmetric cipher algorithm in PHP and its

Hash LookupThe previous lookup algorithm, the time complexity of O (n), or O (㏒2n), its efficiency depends on the number of "comparisons". 即使对于采取排序树结构的查找表，由于每一次比较的结果，如果关键字与数据元素不相等，则有“大于”或者“小于”两个结果，所以下一步会有两种可能的方向，因此O(㏒2n)已经是最优了。Hash table takes

http://blog.csdn.net/kingstar158/article/details/8028635Because of the work needs, for tens other data, the use of stl::map there is really a problem of efficiency, and finally use Boost::unordered_map replace the former, found that there is a great

1. DisclaimerCryptography is a complex topic, and I am not an expert in this field. Many universities and research institutions have long-term research in this area. In this article, I want to try to show you a way to safely store Web program

1. StatementCryptography is a complex topic and I am not an expert in this field. Many universities and research institutions have long-term research in this area. In this article, I would like to try to show you a secure way to store Web

1. StatementCryptography is a complex topic and I am not an expert in this field. Many universities and research institutions have long-term research in this area. In this article, I would like to try to show you a secure way to store Web

Recently want to use a hash function to generate a unique value based on a string, but did not find a good hash function, like PHP built-in MD5, SHA and other hash functions generated by the value is too long, I can not use, want to intercept, and

Recently, I want to use the Hash function to generate a unique value based on a string, but I cannot find a useful Hash function. The value generated by Hash functions such as MD5 and SHA built in PHP is too long, I can't use it. I want to intercept

Basic ConceptsThe so-called perfect hash function refers to a hash function without conflict, that is, to any key1! = Key2 has h (key1 )! = H (key2 ).Set the custom domain to X, the value range to Y, n = | X |, m = | Y |, then there must be m> = n.

1.Hash tableA hash table (hash table, also known as a hash list) is a data structure that is accessed directly from key. That is, it accesses the record by mapping the key to a location in the table to speed up the lookup. This mapping function is

1, hash list (hash table, also known as a hash table), is a data structure that is accessed directly from the key code value (key value). Provides quick insert and find operations, which are based on an array implementation. The basic idea is to map

What is a hash function. A hash function is a mathematical function that has the following three attributes: Enter a string that can be of any size; it produces a fixed-size output; for a specific input string, the result can be calculated at a

Finding discrete logarithms is very difficultRSA is the first letter of the surname of Ron Rivest/adi Shamir/leonard Adleman.RSA can be used for public key cryptography and digital signatures.RSA encryption: Ciphertext = plaintext EMODN (e and N are

PHP, Apache, Perl, and bsddb all use time33 hash. inline unsigned time33 (char const * STR, int Len) { unsigned long hash = 5381; /* variant with the hash unrolled eight times */ for (; Len> = 8; Len-= 8) { hash = (hash hash = (hash hash = (hash

I. Integer Hash Functions There are three common methods: Direct remainder method, Product Integer method, and square method. The three methods are discussed below. The following assumes that our keyword is that the capacity of the hash table is,

oracle| Function | speed When data is stored in a normal table, the records are physically saved to the allocated block in the order they were inserted into the database. For example, if you have a table for storing employee information, the