安裝中文字典英文字典辭典工具!
安裝中文字典英文字典辭典工具!
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- Hash size: Are prime numbers near powers of two a poor choice for the . . .
This answer possibly explains why choosing M(table size) equal to a power of 2 should be avoided Prime numbers that are too close to a power of 2 will provide the same kind of biasing as a power of 2 for the keys which differs by $+a$ or $-a$ if $2^k=a(modulo)M$
- hash - What would happen SHA-256 collision were to be found? - Computer . . .
As far as I and this wikipedia page know, there are no collisions (2 inputs with the same output) found in SHA-256 (yet) what would happen if a collision were to be found, 1 would it be easier to
- hash - How is this the expected number of of probes in open-address . . .
I am reading the "Introduction to Algorithms" by Thomas Cormen et al Particularly the theorem which says that given an open-address hash table with load factor $\alpha = n m < 1$, the expected number of probes in an unsuccessful search is at most $1 (1-\alpha)$, assuming uniform hashing
- 到底什么是哈希值，哈希值到底是怎么生成的，有什么用？ - 知乎
hash值是通过一个计算函数把难以比较的字符串或者其他类型的数据映射成一个整数，最常用的就是映射a～z的hash值，变成hash[(str(i)-‘a’]这个数是一个十进制数，这个十进制数把它映射到0-25，也就是数组下标，但通常来说是映射成1-26，因为方便计算，这是最简单的hash值，然后这个hash值映射成下标
- Hash tables versus binary trees - Computer Science Stack Exchange
In particular, if you're going to need the order on the keys, for example if you want to be able to list the keys in alphabetical order, then hash tables are no help (you'll need to sort them), whereas you can straightforwardly traverse a search tree in order You can combine binary search trees and hash tables in the form of hash trees A hash
- hash - Do passwords need a max length? - Computer Science Stack Exchange
Hash algorithms are designed to produce a practically random output, so for a 24-byte (192-bit) hash, you'd need on the order of $ 2^{96} $ or $ 10^{30} $ inputs to have an approximately 50 % chance of two of them hashing to the same value Due to passwords usually being composed of letters (or nearly enough) and not arbitrary bytes, the hash
- hash - How virtual nodes affects consistent hashing ring? - Computer . . .
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