Separate Chaining Use data structure (such as linked list) to store multiple items that hash to the same slot 1. use linked listCollision: insert item into linked listFind: compute hash value, then do Find on linked list 2. use BSTO(log N) time inste…

hashSet,hashtable,hashMap 都是基于散列函数, 时间复杂度 O(1) 但是如果太差的话是O(n) TreeSet==>O(log(n))==> 基于树的搜索,只需要搜索一半即可 O⑴的原因是离散后,下标对应关键字 hash就是散列,甚至再散列.但是我一直对hash表的时间复杂度有个疑问.一个需要存储的字符串,通过hash函数散列到一个相对较短的索引,使得存取速度加快.但为什么存取的时间复杂度能达到常量级O(1)呢?? 查找时搜索索引不需要费时间吗?为什么不是O(n)呢?…

https://www.javainterviewpoint.com/hashmap-works-internally-java/ How a HashMap Works internally has become a popular question in almost all the interview. As almost everybody knows how to use a HashMap or the difference between HashMap and Hashtable…

1, LinkedList composed of one and one Node: [data][next]. [head] -> [data][next] -> [data][next] -> [data][next] -> [null]. Empty linkedList: head == null. V.S. Array DS: fast at insert/delete. 2, hashtable “数组可以通过下标直接定位到相应的空间”,对就是这句,哈希表的做法其实很…

哈希表 红黑树实现的符号表可以保证对数级别的性能,但我们可以做得更好.哈希表实现的符号表提供了新的数据访问方式,插入和搜索操作可以在常数时间内完成(不支持和顺序有关的操作).所以,在很多情况下的简单符号表,用哈希表实现是最好的选择. hash functions 如果键是小整数,那么我们可以直接使用数组来实现符号表,把键当做数组索引,于是键 i 对应的值放在数组位置 i 上.哈希(散列)是这个简单方法的拓展,可以处理类型更复杂的键.通过数学计算把键转为数组索引,我们就可以用数组来查询(refer…

目标:不要有主要的逻辑错误.2遍以内bug free.注意代码风格 不要让面试官觉得不懂规矩 Java vs C++ Abstract class vs interface  pass by reference vs pass by value Final/Finally/Finalize static 函数参数或者函数中的局部变量和成员变量同名的情况下,成员变量被屏蔽,此时要访问成员变量则需要用“this.成员变量名”的方式来引用成员变量.当然,在没有同名的情况下,可以直接用成员变量的名字,而…

使用Hashtable没有任何优点,因为在.net2.0以后已经被Dictionary<Tkey,TValue>所代替. 他们两者的区别是,根据stackoverflow Dictionary relies on chaining (maintaining a list of items for each hash table bucket) to resolve collisions whereas Hashtable uses rehashing for collision resolut…

What is an entity system framework for game development? Posted on 19 January 2012 Last week I released Ash, an entity system framework for Actionscript game development, and a number of people have asked me the question “What is an entity system fra…

Python dictionary implementation http://www.laurentluce.com/posts/python-dictionary-implementation/ August 29, 2011 This post describes how dictionaries are implemented in the Python language. Dictionaries are indexed by keys and they can be seen as…

General Purpose Hash Function Algorithms post@: http://www.partow.net/programming/hashfunctions/index.html       Description Hashing Methodologies Hash Functions and Prime Numbers Bit Biases Various Forms Of Hashing String Hashing Cryptographic Hashi…