hashmap

Setting hash salt for individual calls [duplicate]

由 谁说我不能喝 提交于 2020-01-16 21:35:45
问题 This question already has answers here : Disable hash randomization from within python program (2 answers) Closed 3 years ago . I'm looking for a way to set python's hash() salt for individual calls to the function. In the docs, I've only found PYTHONHASHSEED which sets the salt for all calls to hash() . However, I need hash to always get me the same result when called by specific objects, but I don't want to force the entire application to use the same (predictable) salt. Context: In python2

Setting hash salt for individual calls [duplicate]

由 纵饮孤独 提交于 2020-01-16 21:35:33
问题 This question already has answers here : Disable hash randomization from within python program (2 answers) Closed 3 years ago . I'm looking for a way to set python's hash() salt for individual calls to the function. In the docs, I've only found PYTHONHASHSEED which sets the salt for all calls to hash() . However, I need hash to always get me the same result when called by specific objects, but I don't want to force the entire application to use the same (predictable) salt. Context: In python2

HashMap实现原理

由 旧时模样 提交于 2020-01-16 18:48:47
之前面试，有大量公司问了这个问题，坐标上海，所以这里记一下。 首先，HashMap使用的是 数组+链表 的数据结构进行存储。 HashMap在存储元素的时候，首先对key进行一个HashCode()方法，然后将这个元素存入到数组中，如果发现当前数组中已经有元素，即为hash冲突，此时会以数组中当前元素为首开辟一个链表，调用key的equals()方法将数据存入。 获取元素时，通过key的hashCode()方法可以找到元素存放在数组中的位置，如果发现存在多个元素（链表中），则调用key的equals方法找到具体的元素返回。 因为可能存在hash冲突，所以在重写hashcode方法时也最好重写equals方法。 对于数组中的每一个元素下的链表，它们的hashCode值一定是相同的。如果两个对象连hashCode都不相等，那这两个对象一定不等。即： 两个对象hashCode相等，equals相等，两个对象才相等；相反，两个对象相等，则hashCode和equals一定相等。 两个对象hashCode不相等，那不用比较equals了，两个对象一定不相等；而两个对象不相等，则hashCode可能相等，但equals一定不相等。 来源： CSDN 作者： 我爱我的宝可梦 链接： https://blog.csdn.net/weixin_42362544/article/details

Struct members who are traits that use associated types

由 北慕城南 提交于 2020-01-16 16:31:28
问题 I have a follow up question to this question: Expose a HashMap in a generic way that disregards the HashMap value Suppose I want to use HashMapContainer (the same one that was defined in the previous question's first answer) as a member in another struct (let's call it MyDB ) and in MyDB constructor I want to decide whether to construct this member as HashMapContainerImpl1 or HashMapContainerImpl2 . I don't want to define MyDB as a template (e.g MyDB<T> ) because MyDB users don't care about

Struct members who are traits that use associated types

由 你说的曾经没有我的故事 提交于 2020-01-16 16:31:12
问题 I have a follow up question to this question: Expose a HashMap in a generic way that disregards the HashMap value Suppose I want to use HashMapContainer (the same one that was defined in the previous question's first answer) as a member in another struct (let's call it MyDB ) and in MyDB constructor I want to decide whether to construct this member as HashMapContainerImpl1 or HashMapContainerImpl2 . I don't want to define MyDB as a template (e.g MyDB<T> ) because MyDB users don't care about

listview lazyadapter

由 ▼魔方 西西 提交于 2020-01-16 13:58:08
问题 I like to pass selected item value from ListView to another activity. I am using this code to get the details associated with the hashmap but I get java.lang.Integer cannot be cast to java.util.HashMap . public void onItemClick(AdapterView<?> parent, View view, int position, long id) { HashMap<String, String> o = (HashMap<String, String>) list.getItemAtPosition(position); Toast.makeText(CustomizedListView.this, "ID '" + o.get("KEY_TITLE") + "' was clicked.", Toast.LENGTH_SHORT).show(); } How

listview lazyadapter

由 ⅰ亾dé卋堺 提交于 2020-01-16 13:57:43
问题 I like to pass selected item value from ListView to another activity. I am using this code to get the details associated with the hashmap but I get java.lang.Integer cannot be cast to java.util.HashMap . public void onItemClick(AdapterView<?> parent, View view, int position, long id) { HashMap<String, String> o = (HashMap<String, String>) list.getItemAtPosition(position); Toast.makeText(CustomizedListView.this, "ID '" + o.get("KEY_TITLE") + "' was clicked.", Toast.LENGTH_SHORT).show(); } How

How to properly malloc item in struct array hashmap in C

由 こ雲淡風輕ζ 提交于 2020-01-16 09:11:30
问题 In the following code, I'm using malloc for adding a new item to a hashmap. I thought I've checked all the boxes for properly using malloc, but valgrind says I've got a memory leak on them. Can someone point me to where I've gone wrong? #include <stdlib.h> #include <string.h> typedef struct node { char content[46]; struct node* next; } node; typedef node* hashmap_t; int main (int argc, char *argv[]) { hashmap_t hashtable[1000]; node *n = malloc(sizeof(node)); if(n == NULL) return 0; hashmap_t

Two-sum Leetcode explanation, Hashmap, Javascript

由 杀马特。学长 韩版系。学妹 提交于 2020-01-16 08:38:12
问题 Im just wondering who can explain the algorithm of this solution step by step. I dont know how hashmap works. Can you also give a basic examples using a hashmap for me to understand this algorithm. Thank you! var twoSum = function(nums, target) { let hash = {}; for(let i = 0; i < nums.length; i++) { const n = nums[i]; if(hash[target - n] !== undefined) { return [hash[target - n], i]; } hash[n] = i; } return []; } 回答1: Your code takes an array of numbers and a target number/sum. It then

集合总结

由 半世苍凉 提交于 2020-01-16 02:38:10
Java集合，不再使用过多的文字描述，为了更加清晰的展示集合之间的关系，本文使用一张导图阐述整个集合，之后会针对几个类似的类，进行对比说明： 1、集合接口有哪些，主要包含哪些实现类 Collection：ArrayList，LinkedList，Vector，HashSet，TreeSet，LinkedHashSet，Queue Map：HashMap，WeekHashMap，TreeMap，ConcurrentHashMap，HashTable 2、ArrayList和Vector的区别 1）Vector使用了Synchronized关键字，是线程安全的，ArrayList是线程不安全的。 2）Vector扩容时2n，ArrayList是1.5n+1 3、ArrayList和LinkedList的区别 1）ArrayList底层为数组，LinkedList为双向链表 2）ArrayList在查找效率更高，而LinkedList在增删效率高 4、ConcurrentHashMap与HashTable的区别 ConcurrentHashMap本身的数据结构与hashMap大致一致，但是引入了分段锁，将锁住某一个segment，而HashTable锁住的是整个结构 5、HashMap与HashTable的区别 1）HashMap是线程不安全的，HashTable是线程安全的 2
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