1//头文件unorder_map,2template<classKey,3classTy,4classHash = std::hash<Key>,5classPred = std::equal_to<Key>,6classAlloc = std::allocator<std::pair<constKey, Ty> > >7classunordered_map;8>classunordered_map 一、map按键值Key排序 1. 默认按照less<key>升序排列 输入8,Key升序,Value随机...
buckets[hashFunction(key) % capacity].emplace_back(key, ValueType()); size++; return buckets[hashFunction(key) % capacity].back().second; } } void erase(const KeyType& key) { size_t bucketIndex = hashFunction(key) % capacity; Bucket& bucket = buckets[bucketIndex]; for (auto it = ...
自己一翻折腾并大牛的热心帮助下终于有所明白,简单说来,unordered_map继承自_Hash类型,_Hash用到一个_Uhash_compare类来封装传入的hash函数,如果unordered_map构造函数没有显示的传入hash函数实例引用,则unordered_map默认构造函数使用第三个模板参数指定的Hash类型的默认构造函数,进行hash函数实例的默认构造。在第一种...
std::unordered_map<Key,T,Hash,KeyEqual,Allocator>::begin, std::unordered_map<Key,T,Hash,KeyEqual,Allocator>::cbegin std::unordered_map<Key,T,Hash,KeyEqual,Allocator>::empty std::unordered_map<Key,T,Hash,KeyEqual,Allocator>::end, std::unordered_map<Key,T,Hash,KeyEqual,Allocator>::cend...
Hash policy unordered_map::load_factor unordered_map::max_load_factor unordered_map::rehash unordered_map::reserve Observers unordered_map::hash_function unordered_map::key_eq Non-member functions operator==operator!= (C++11)(C++11)(until C++20) ...
注意:函数对象:即调用操作符的类,其对象常称为函数对象(function object),它们是行为类似函数的对象。表现出一个函数的特征,就是通过“对象名+(参数列表)”的方式使用一个 类,其实质是对operator()操作符的重载。1 #include<iostream> 2 #include<map> 3 using namespace std; 4 typedef struct tagIntPlus 5...
std::unordered_map<Key,T,Hash,KeyEqual,Allocator>::hash_function From cppreference.com <cpp |container |unordered map C++ hasher hash_function()const; (since C++11) Returns the function that hashes the keys. Parameters (none)
给定unordered_map的实例c: 1)平均情况:常数,最坏情况:c.size() 2)平均情况:std::distance(first, last),最坏情况:c.size() 3)平均情况:c.count(key),最坏情况:c.size() 示例 运行此代码 #include <unordered_map>#include <iostream>intmain(){std::unordered_map<int,std::string>c={{1,"one"...
1. 哈希表(unordered_map)和黑红树(map)简介以及初始化 1.1 哈希表的基本介绍 哈希表(Hash table),或称散列表,在英语口语中我们通常称其为 “hash map” 或“unordered map”。在一次性解析语句时,我们可能会说,“Hash table, also known as hash map or unordered map, is a data structure that implement...
#include <iostream>#include <string>#include <unordered_map>intmain(){std::unordered_map<int,std::string>dict={{1,"one"},{2,"two"}};dict.insert({3,"three"});dict.insert(std::make_pair(4,"four"));dict.insert({{4,"another four"},{5,"five"}});constboolok=dict.insert({1,...