HDU 1509 Windows Message Queue 【优先队列】

最新推荐文章于 2020-03-04 18:21:17 发布

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最新推荐文章于 2020-03-04 18:21:17 发布

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分类专栏：栈|队列文章标签：栈|队列

本文链接：https://blog.youkuaiyun.com/LOOKQAQ/article/details/81268181

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本文介绍了一个消息队列的模拟实现，使用优先队列结构按消息的优先级进行排序，优先级越低的消息越先被处理。若两个消息优先级相同，则按照先进先出的原则处理。代码实现了消息的添加和获取功能。

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题目链接：http://acm.hdu.edu.cn/showproblem.

思路：先按照priority进行排序，prirority越低则该组输入信息越先输出，priority相同的话，按照先来后到的顺序输出。用优先队列解决。代码如下：

//#include<bits/stdc++.h> 
#include<iostream>
#include<algorithm>
#include<queue>
using namespace std;
struct node{
	string s;
	int s1;
	int s2;
	int num;
};
bool operator< (node a,node b)
{
	if(a.s2==b.s2)   //priority相同时，按照先来后到的顺序进行排序 
	  return a.num>b.num;
	return a.s2>b.s2;  //按照priority排序，越低优先级越高
}
int main()
{
	int k=0;
	char str[5];
	priority_queue<node>que;
	node Node;
	while(cin>>str)
	{
		if(str[0]=='P')  // 当输入的字符串的首字母是P时，继续输入，存入队列中 
		{
			cin>>Node.s>>Node.s1>>Node.s2;
			Node.num=k++;   //k++是为了保证排序时 priority相同时，按照先来后到的顺序进行排序 
			que.push(Node);
		}
		else
		{
			if(que.empty())
			   cout<<"EMPTY QUEUE!"<<endl;
			else
			 {
			 	Node=que.top();
			 	que.pop();
			 	cout<<Node.s<<" "<<Node.s1<<endl;
			 }
		}
	}
	que.pop();
	return 0;
}

ps：无形之刃，最为致命！

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 8915 Accepted Submission(s): 3678

Problem Description

Message queue is the basic fundamental of windows system. For each process, the system maintains a message queue. If something happens to this process, such as mouse click, text change, the system will add a message to the queue. Meanwhile, the process will do a loop for getting message from the queue according to the priority value if it is not empty. Note that the less priority value means the higher priority. In this problem, you are asked to simulate the message queue for putting messages to and getting message from the message queue.

Input

There's only one test case in the input. Each line is a command, "GET" or "PUT", which means getting message or putting message. If the command is "PUT", there're one string means the message name and two integer means the parameter and priority followed by. There will be at most 60000 command. Note that one message can appear twice or more and if two messages have the same priority, the one comes first will be processed first.(i.e., FIFO for the same priority.) Process to the end-of-file.

Output

For each "GET" command, output the command getting from the message queue with the name and parameter in one line. If there's no message in the queue, output "EMPTY QUEUE!". There's no output for "PUT" command.

Sample Input

GET PUT msg1 10 5 PUT msg2 10 4 GET GET GET

Sample Output

EMPTY QUEUE! msg2 10 msg1 10 EMPTY QUEUE!