一、用法

二、应用

#include<iostream>
#include<map>
using namespace std;
struct studentinfo
{
	int id;
	char name[20];
};
struct student   //multimap容器内元素是pair形式
{
	int score;
	studentinfo info;
};
typedef multimap<int, studentinfo> MAP_STD;
int main() 
{
	MAP_STD mp;
	student st;
	char cmd[20];
	while (cin >> cmd)
	{
		if (cmd[0] == 'A')
		{
			cin >> st.info.name >> st.info.id >> st.score;
			mp.insert(make_pair(st.score, st.info));   //使得输入以pair形式存入
		}
		else if (cmd[0] == 'Q')
		{
			int score;
			cin >> score;
			auto p = mp.lower_bound(score);
			if (p != mp.begin())
			{
				--p;
				score = p->first;
				MAP_STD::iterator maxp = p;
				int maxid = p->second.id;
				for (; p != mp.begin() && p->first == score; --p)
				{
					if (p->second.id > maxid)
					{
						maxp = p;
						maxid = p->second.id;
					}
				}
				if (p->first == score)  //即是因为指向begin()跳出，此时仍需比较
				{
					if (p->second.id > maxid)
					{
						maxp = p;
						maxid = p->second.id;
					}
				}
				cout << maxp->second.name << " " << maxp->second.id << " " << maxp->first << endl;
			}
			else  //即p==mp.begin() 没有比其更低的了
				cout << "Nobody" << endl;
		}
	}
	system("pause");
}