一、题目描述
二、解题思路
每次都要找优先级最高的,这明显是采用优先队列来解决,结合Hash表快速对优先级所对应的消息进行快速定位,最后把输出信息保存到一个队列里,结束时一起输出,但是不保存到队列直接输出也可以
- 知识点:对于优先队列内的元素是自定义类型,那么通过友元函数进行运算符重载来决定堆是小根堆还是大根堆
class Msg{
public:
char msg[10];
int priority;
friend bool operator<(Msg a, Msg b)
{
return a.priority > b.priority;
}
};
priority_queue<Msg> Heap; //小根堆
三、解题代码
#include <cstdio>
#include <queue>
using namespace std;
class Msg
{
public:
char msg[10];
int priority;
friend bool operator<(Msg a, Msg b)
{
return a.priority > b.priority;
}
};
int main()
{
priority_queue<Msg> Heap;
int N;
scanf("%d", &N);
for (int i = 0; i < N; i++)
{
char CMD[10];
scanf("%s", CMD);
if (CMD[0] == 'P')
{
Msg tmp_msg;
scanf("%s", tmp_msg.msg);
scanf("%d", &tmp_msg.priority);
Heap.push(tmp_msg);
}
if (CMD[0] == 'G')
{
if (Heap.empty())
printf("EMPTY QUEUE!\n");
else
{
printf("%s\n", Heap.top().msg);
Heap.pop();
}
}
}
return 0;
}