设计hashtable时,size一般是prime number, 这是为什么呢。。。算法hash 有用7关注1收藏4 回复 阅读8.2k 3 个回答 得票最新 justjavac 47.8k744111 发布于 2013-06-19 你肯定没有听说过 17年蝉 的故事吧。 用质数是为了防止冲突。比如一个hashtable(长度为3)的哈希算法是: a[0]*1 + a[1]*2 + a[...
The modulus is taken with the hash table size (a prime number) to find the ‘bucket’ to place each key into. The function should also be very fast, since it is called for each key lookup. 一个好的散列函数应该产生在相当大的范围内均匀分布的散列值。 模数与哈希表大小(质数)一起使用,以...
The first thing you do when inserting/retreiving from hash table is to calculate the hashCode for the given key and then find the correct bucket by trimming the hashCode to the size of the hashTable by doing hashCode % table_length. Here are 2 statements that you most probably have read ...
The size of the hash table is a prime number. Using open addressing + quadratic probing to resolve conflicts. To ensure that new entries can be inserted, the load factor of the hash table cannot exceed (please fill in decimal). 散列表的规模是素数,用开放定址+平方试探法排解冲突,若要保证新...
从概率上来说,是很有可能的. 在Hash Table 中叫做collision. 所以, 一个完备的Hash Table 必须有个planB 去解决这样的现象. 另外,Hash Table 的长度是预先设定好的(最好是prime number--质数->137), 但长度是可变的。 其中, 初始化一个Hash Table的长度真的是一个数学问题, 关系到构建一个hash function的...
* prime number close to the "suggested" number of elements that will * be in the hash table. Use 16 as the minimum hash table size. * * Ref: Sedgewick, Algorithms in C, "Hash Functions" * * Up to ~250,000 buckets, we use powers of 2. After that, we slow ...
// Choose a prime number for the hash table size, to achieve a uniform distribution: static final intSIZE=997; // You can't have a physical array of generics, but you can upcast to one: @SuppressWarnings("unchecked") LinkedList<MapEntry<K,V>>[]buckets= ...
Let P(x) = x2, keep the table size a prime number > 3 and also α(Max load factor) <= ½.Let P(x) = (x2 + x)/2, keep the table size a power of two.Let P(x) = (-1x)*x2, keep the table size a prime number N where N ≡ 3 mod 4. Now let’s test one of...
as all keys would hash to even values if they happened to be even. IfHASH_TABLE_SIZEis a power of two, then the hash function simply selects a subset of thekeybits as the table index. To obtain a more random scattering,HASH_TABLE_SIZEshould be a prime number not too close to a po...
hash table 英[hæʃ ˈteibl] 美[hæʃ ˈtebəl] 释义 杂凑(哈希)表 实用场景例句 全部 Problem Description: Designhash tableto achieve telephone number inquiry system. 问题描述: 设计哈希表实现电话号码查询系统. 互联网 So, this implementation uses a prime number for thehash tablesize...