【HDU 1509】Windows Message Queue（栈-水题）

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Windows Message Queue

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)

Total Submission(s): 7281    Accepted Submission(s): 2951


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!

 

Author

ZHOU, Ran

 

Source

Zhejiang University Local Contest 2006, Preliminary

 
题意：按照提示输入信息，get输出信息

题解：栈的水题，简单的入栈出栈操作。

代码：

#include <iostream>
#include <cstring>
#include <cmath>
#include <queue>
#include <vector>
#include <cstdio>
#include <map>

using namespace std;

struct Message
{
char msg[20];
int pri; //权值
int par; //参数
int t; //记录当前message是具有相同键值的所有message中的第几个
};
priority_queue<Message> Q;
map<int, int> M;

bool operator < (const Message& a, const Message& b)
{
if(a.pri != b.pri) return a.pri > b.pri;
return a.t > b.t;
}

int main()
{
char cmd[4];
while(scanf("%s", cmd) != EOF)
{
if(cmd[0] == 'P')
{
Message newMsg;
scanf("%s %d %d", newMsg.msg, &newMsg.par, &newMsg.pri);
newMsg.t = M[newMsg.pri]++; //map的作用在此
Q.push(newMsg);
}
else
{
if(Q.empty()) puts("EMPTY QUEUE!");
else
{
Message outMsg = Q.top();
Q.pop();
printf("%s %d\n", outMsg.msg, outMsg.par);
}
}
}
return 0;
}