HOJ 1873 看病要排队（优先级队列 priority_queue, 巨水）

优先级队列 priority_queue, 巨水
本题要点：
1、定义一个结构体 person 来描述病人的信息，
int enter_id; //进场顺序
int priority; //优先级
重写运算符< , 注意，先按 优先级从小到大，在按进场顺序从大到小。
2、3个医生，每个医生前面都有一条队列。 模拟医生看病顺序。

#include <cstdio>
#include <cstring>
#include <iostream>
#include <queue>
using namespace std;
const int MaxN = 2010;
int n;
char cmd[10];

struct person
{
	int enter_id;	//进场顺序
	int priority;	//优先级
	bool operator<(const person & rhs) const
	{
		if(priority != rhs.priority)
			return priority < rhs.priority;
		return enter_id > rhs.enter_id;
	}
};

void solve()
{
	priority_queue<person> q[4];
	int doctor, priority_id;
	person per;
	int cnt = 0;
	for(int i = 0; i < n; ++i)	
	{
		scanf("%s", cmd);
		if(cmd[0] == 'I')
		{
			scanf("%d%d", &doctor, &priority_id);
			per.enter_id = ++cnt, per.priority = priority_id;
			q[doctor].push(per);
		}else{
			scanf("%d", &doctor);
			if(!q[doctor].size())
			{
				printf("EMPTY\n");
			}else{
				per = q[doctor].top();q[doctor].pop();
				printf("%d\n", per.enter_id);
			}
		}
	}
}

int main()
{
	while(scanf("%d", &n) != EOF)
	{
		solve();
	}
	return 0;
}

/*
7
IN 1 1
IN 1 2
OUT 1
OUT 2
IN 2 1
OUT 2
OUT 1
2
IN 1 1
OUT 1
*/

/*
2
EMPTY
3
1
1
*/