C++ 关联容器使用 map, unordered_map, set, unordered_set, multiset, unordered_multiset

关联容器	是否有序	是否关联值	是否可重复	访问时间
set	是	否	否	对数
map	是	是	否	对数
multiset	是	否	是	对数
multimap	是	是	是	对数
unordered_map	否	是	否	常数
unordered_set	否	否	否	常数
unordered_multiset	否	否	是	常数
unordered_multimap	否	是	是	常数

#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <iostream>
#include <array>using namespace std;template <typename AssozCont>
bool containsElement5(const AssozCont& assozCont) {return assozCont.contains(5);
}int main() {// std::mapstd::map<std::string, int> m{ {"Dijkstra", 1972}, {"Scott", 1976} };m["Ritchie"] = 1983;std::cout << m["Ritchie"]; // 1983for (auto p : m) std::cout << "{" << p.first << "," << p.second << "}";// {Dijkstra,1972},{Ritchie,1983},{Scott,1976}m.erase("Scott");for (auto p : m) std::cout << "{" << p.first << "," << p.second << "}";// {Dijkstra,1972},{Ritchie,1983}m.clear();std::cout << m.size() << std::endl; // 0// std::unordered_mapstd::unordered_map<std::string, int> um{ {"Dijkstra", 1972}, {"Scott", 1976} };um["Ritchie"] = 1983;std::cout << um["Ritchie"]; // 1983for (auto p : um) std::cout << "{" << p.first << "," << p.second << "}";// {Ritchie,1983},{Scott,1976},{Dijkstra,1972}um.erase("Scott");for (auto p : um) std::cout << "{" << p.first << "," << p.second << "}";// {Ritchie,1983},{Dijkstra,1972}um.clear();std::cout << um.size() << std::endl; // 0// std::setstd::set<int> mySet{ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };std::cout << "containsElement5(mySet): "<< containsElement5(mySet); // true//std::unordered_setstd::unordered_set<int> myUnordSet{ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };std::cout << "containsElement5(myUnordSet): "<< containsElement5(myUnordSet); // true// std::multisetstd::multiset<int> myMuliSet{ 3, 1, 5, 3, 4, 5, 1, 4, 4, 3, 2, 2, 7, 6, 4, 3, 6 };for (auto s : myMuliSet) std::cout << s << " ";// 1 1 2 2 3 3 3 3 4 4 4 4 5 5 6 6 7myMuliSet.insert(8);std::array<int, 5> myArr{ 10, 11, 12, 13, 14 };myMuliSet.insert(myArr.begin(), myArr.begin() + 3);myMuliSet.insert({ 22, 21, 20 });for (auto s : myMuliSet) std::cout << s << " ";// 1 1 2 2 3 3 3 3 4 4 4 4 5 5 6 6 7 10 11 12 20 21 22std::cout << myMuliSet.erase(4); // 4myMuliSet.erase(myMuliSet.lower_bound(5), myMuliSet.upper_bound(15));for (auto s : myMuliSet) std::cout << s << " ";// 1 1 2 2 3 3 3 3 20 21 22// std::multimapstd::multimap<char, int> multiMap = { {'a', 10}, {'a', 20}, {'b', 30} };for (auto p : multiMap) std::cout << "{" << p.first << "," << p.second << "} ";// {a,10} {a,20} {b,30}return 0;}