POJ 3481 Double Queue （STL SET）

题意：

        模拟一个有序双端队列，可以执行如下操作

        0 代表停机

        1  X  Y 代表插入一个数 X 它的权重为 Y

        2  代表输出权重最大的数并从队列中删除

        3  代表输出权重最小的数并从队列中删除

思路：

       利用 set 直接写就行。

代码：

#include <iostream>#include <set>#include <cstdio>using namespace std;typedef struct Node{    int x;    int y;    Node(int xx=0,int yy=0){x=xx;y=yy;}    bool operator < (const Node a)const{        return a.y>y;    }}Node;set <Node> sett;set <Node> ::iterator it;int main(){    int t,x,y;    while(scanf("%d",&t)&&t){        if(t==1){            scanf("%d%d",&x,&y);            sett.insert(Node(x,y));        }else if(t==2){            if(sett.empty()) printf("0\n");            else{                it=sett.end();                it--;                printf("%d\n",it->x);                sett.erase(it);            }        }else{            if(sett.empty()) printf("0\n");            else{                it=sett.begin();                printf("%d\n",it->x);                sett.erase(it);            }        }    }}

The new founded Balkan Investment Group Bank (BIG-Bank) opened a new office in Bucharest, equipped with a modern computing environment provided by IBM Romania, and using modern information technologies. As usual, each client of the bank is identified by a positive integer K and, upon arriving to the bank for some services, he or she receives a positive integer priority P. One of the inventions of the young managers of the bank shocked the software engineer of the serving system. They proposed to break the tradition by sometimes calling the serving desk with thelowest priority instead of that with the highest priority. Thus, the system will receive the following types of request:

0The system needs to stop serving1 KPAdd client K to the waiting list with priority P2Serve the client with the highest priority and drop him or her from the waiting list3Serve the client with the lowest priority and drop him or her from the waiting list

Your task is to help the software engineer of the bank by writing a program to implement the requested serving policy.

Input

Each line of the input contains one of the possible requests; only the last line contains the stop-request (code 0). You may assume that when there is a request to include a new client in the list (code 1), there is no other request in the list of the same client or with the same priority. An identifier K is always less than 10⁶, and a priority P is less than 10⁷. The client may arrive for being served multiple times, and each time may obtain a different priority.

Output

For each request with code 2 or 3, the program has to print, in a separate line of the standard output, the identifier of the served client. If the request arrives when the waiting list is empty, then the program prints zero (0) to the output.

Sample Input

21 20 141 30 321 10 993220

Sample Output

02030100