HDU 1509:Windows Message Queue【优先队列】

Windows Message Queue

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

Total Submission(s): 4505    Accepted Submission(s): 1794


[align=left]Problem Description[/align]
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.
 

[align=left]Input[/align]
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.
 

[align=left]Output[/align]
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.
 

[align=left]Sample Input[/align]

GET
PUT msg1 10 5
PUT msg2 10 4
GET
GET
GET 结构体里定义排序的时候我直接用了（node a,node b)，然后一直WA。。。。。纠结了老半天～百度了之后才知道应该用（const node& a,const node& b)虽然不知道为什么～～AC-code：

#include<stdio.h>
#include<string.h>
#include<queue>
using namespace std;
struct node
{
int k;
char s[100];
int name;
int pri;
friend bool operator<(const node& a,const node& b)
{
if(a.pri==b.pri)
return a.k>b.k;
return a.pri>b.pri;
}
};
int main()
{
char a[5];
node no;
int k=1;
priority_queue<node>q;
while(scanf("%s",a)!=EOF)
{
if(!strcmp(a,"PUT"))
{
scanf("%s%d%d",no.s,&no.name,&no.pri);
no.k=k++;
q.push(no);
}
else
{
if(q.empty())
{
printf("EMPTY QUEUE!\n");
}
else
{
printf("%s %d\n",q.top().s,q.top().name);
q.pop();
}
}
}
return 0;
}

 

[align=left]Sample Output[/align]

EMPTY QUEUE!
msg2 10
msg1 10
EMPTY QUEUE!