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- 什么是 hash？ - 知乎
提到hash，相信大多数同学都不会陌生，之前很火现在也依旧很火的技术区块链背后的底层原理之一就是hash，下面就从hash算法的原理和实际应用等几个角度，对hash算法进行一个讲解。 1、什么是Hash Hash也称散列、哈希，对应的英文都是Hash。
- hash算法的数学原理是什么，如何保证尽可能少的碰撞？ - 知乎
我来解释一下为什么s一般取值为131，使用为前面的字符串数组a[n]中，取得的字符的为ascii码，数值<=127，为了尽可能保证获取的hash值的唯一性，因此需要让s为一个大于127的质数，而为了提高散列密度，又要使s尽可能小，因此，大于127的最小质数，就是131。 这个值具有最佳的散列质量和散列密度。
- cryptography - Given a string, is it possible to determine which . . .
2) a definite hash of a specific hashing algorithm? Possible methods: 1) For hashes susceptible to rainbow-table attacks, it would be viable to search for the hash in such a rainbow table for various algorithms, to find a match; if a match is found, we know which algorithm produced it
- 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
由于他的调皮，导致客户挑妹纸的时间大幅延长，从10秒到了800秒。 在代码中，一般都有一些比较复杂的算法去运算而得出这个hash值，一旦破解了这个算法，就又可以调皮啦。 在JAVA中，hash算法在HashMap中有体现，有兴趣的可以去看看源码。
- hash tables - Number of probes in a successful search in open address . . .
Given an open-address hash table with α α < 1, the expected number of probes in a successful search is at most 1 αln 1 1−α 1 α ln 1 1 α I read this in a book and the proof starts by saying Searching for k follows the same probe sequence as inserting it If k k is the i + 1 i + 1 th key inserted into the table, then 1 1− i m 1 1 m is the maximum expected number of probes for the
- 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 $\\alpha = n m lt; 1$, the expected
- What is the advantage of seperate chaining over open addressing?
Hash tables resolve collisions through two mechanisms, separate chaining or open hashing and open addressing or closed hashing Though the first method uses lists (or other fancier data structure) in hash table to maintain more than one entry having same hash values, the other uses complex ways of skipping n elements on collsion
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