本文出自:http://blog.csdn.net/svitter
题目12：计算机学院学生会的打印机（优先队列）
小明抱怨学生会的打印机不符合FIFO的原则，看到很多在他后面来打印的同学比他先打印出来。五分钟前，小明的文件就是下一个候选的，如今小明的文件又排到了后面。学生会的同学给小明解释说，学生会的打印机不是採用传统的队列方式，而是採用一种自定义的优先队列方式：每一个要打印的文件被赋予了一个从1到9的优先级（9最高，1最低）。打印规定例如以下：
将队列中要打印的文件f从队列中拿出来；
假设在队列中有优先级高于f的文件，则不打印f，将f排到队列的最后；否则打印f。
小明知道打印新规以后，询问他的文件到底多长时间可以打印出来，如果没分文件打印的时间都是1分钟，小明的文件在打印队列中，而且不再有新的文件进入到打印队列。请你帮助小明计算一下他还须要等多长时间。建议完毕人数1人。
加入了小元素的筛选代码
PriorityQueue.cpp:
//============================================================================
// Name : PriorityQueue.cpp
// Author : vit
// Version :
// Copyright : Your copyright notice
// Description : Hello World in C++, Ansi-style
//============================================================================#include <iostream>
#include <stdio.h>
#include "Queue.h"
using namespace std;int main() {Queue *q;q = new Queue();int i;int n, m, val, num;int mval;Node *p;freopen("test", "r", stdin);while(~scanf("%d%d", &n, &m)){num = 1;for(i = 1; i <= n; i++){scanf("%d", &val);//printf("第%d号正在增加队列...\n", i);p = new Node(val, NULL, i);if(i == m){mval = val;}q->push(p);}q->check(mval);//printf("队列增加完毕。\n");while(!q->IsEmpty()){p = q->top();//printf("当前打印的是第%d号\n", p->num);if(p->num == m){printf("小明在第%d分钟打印。\n", num);}q->pop();num++;}}return 0;
}
Queue.cpp:
/** Queue.cpp** Created on: 2014Äê6ÔÂ15ÈÕ* Author: vit*/#include <stdio.h>
#include "Queue.h"Queue::Queue() {// TODO Auto-generated constructor stubthis->front = this->rear = NULL;
}bool Queue::IsEmpty(){return this->rear == NULL;
}void Queue::push(Node *n){if(IsEmpty()){this->front = this->rear = n;}else{this->rear->next = n;this->rear = n;}return;
}void Queue::pop(){if(IsEmpty()){return;}Node *p = this->front;if(this->front == this->rear){p = this->front;this->front = this->rear = NULL;}else{p = this->front;this->front = this->front->next;}delete p;
}Node * Queue::top(){if(IsEmpty()){return NULL;}int value = this->front->value;Node *p = this->front;while(p->next != NULL){if(p->next->value <= value)p = p->next;else{this->rear->next = this->front;this->rear = p;this->front = p->next;p->next = NULL;p = this->front;value = p->value;}}return this->front;
}void Queue::check(int mval)
{Node *p = this->front;Node *temp;while(p->next != NULL){if(p->next->value < mval){temp = p->next;p->next = p->next->next;delete temp;}//p指向下一个节点p = p->next;}
}Queue::~Queue() {// TODO Auto-generated destructor stubwhile(!IsEmpty()){Node *temp;temp = this->front;this->front= this->front->next;delete temp;}
}
Queue.h:
/** Queue.h** Created on: 2014年6月15日* Author: vit*/#ifndef QUEUE_H_
#define QUEUE_H_class Node
{
public:int value;int num;Node *next;Node(){this->value = 0;this->num = 0;this->next = 0;}Node(int value, Node *next, int num){this->value = value;this->next = next;this->num = num;}
};class Queue
{
public:Queue();virtual ~Queue();//methodvoid push(Node *n);void pop();Node* top();bool IsEmpty();void check(int mval);//memberNode *front;Node *rear;
};
#endif /* QUEUE_H_ */
)
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