Windows Message Queue（优先队列）

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Windows Message Queue

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 4400    Accepted Submission(s): 1747

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!

 题解：优先队列，要考虑同一优先级时的出列顺序；由于优先队列当优先级相同时随机输出队列，所以加一个z；否则wa；

代码：

#include<stdio.h>
#include<string.h>
#include<queue>
using namespace std;
const int MAXN=60010;
struct Node{
    char ms[20];
    int x,y,z;
    friend bool operator < (Node a,Node b){
        if(a.y!=b.y)return a.y > b.y;
    else return a.z>b.z;
}
};
Node people;
int main(){int k=0;
    char temp[5];priority_queue<Node>message;
    while(memset(temp,0,sizeof(temp)),scanf("%s",temp)!=EOF){
        if(!strcmp(temp,"GET")){
            if(message.empty())puts("EMPTY QUEUE!");
            else printf("%s %d
",message.top().ms,message.top().x),message.pop();
        }
        else if(!strcmp(temp,"PUT"))k++,scanf("%s %d %d",people.ms,&people.x,&people.y),people.z=k,message.push(people);
    }
    return 0;
}