multimap 和 multiset 是 C++ 标准库 (STL) 中的两种有序关联容器，它们是 map 和 set 的“多重 (multi)”版本。(允许重复)
Which to Use?
Map
A faster one
auto i = std::find(m.begin(), m.end(), elemToFind);
if(i == m.end())
std::cout << "Non-Exist" << std::endl;
else
std::cout << "Is Found" << std::endl;#include <iostream>
#include <vector>
#include <map>
int main()
{
std::map<int, int> m;
std::cout << m.count(1) << std::endl; // 0
m[1];
std::cout << m[1] << std::endl; // 0
std::cout << m.count(1) << std::endl; // 1
std::cout << m.count(2) << std::endl; // 0
m.at(2);
/*terminate called after throwing an instance of 'std::out_of_range'
what(): map::at*/
std::cout << m.count(2) << std::endl; // Not be run
return 0;
}
Set
Multimap
auto range = scores.equal_range("Alice");
for (auto it = range.first; it != range.second; ++it) {
cout << it->first << " = " << it->second << endl;
}