PAT A 1017.Queueing at Bank (25)

题目

Suppose a bank has K windows open for service. There is a yellow line infront of the windows which devides the waiting area into two parts. All thecustomers have to wait in line behind the yellow line, until it is his/her turnto be served and there is a window available. It is assumed that no window canbe occupied by a single customer for more than 1 hour.

Now given the arriving time T and the processing time P of each customer,you are supposed to tell the average waiting time of all the customers.

Input Specification:

Each input file contains one test case. For each case, the first linecontains 2 numbers: N (<=10000) - the total number of customers, and K(<=100) - the number of windows. Then N lines follow, each contains 2 times:HH:MM:SS - the arriving time, and P - the processing time in minutes of acustomer. Here HH is in the range [00, 23], MM and SS are both in [00, 59]. Itis assumed that no two customers arrives at the same time.

Notice that the bank opens from 08:00 to 17:00. Anyone arrives early willhave to wait in line till 08:00, and anyone comes too late (at or after17:00:01) will not be served nor counted into the average.

Output Specification:

For each test case, print in one line the average waiting time of all thecustomers, in minutes and accurate up to 1 decimal place.

Sample Input:

7 3

07:55:00 16

17:00:01 2

07:59:59 15

08:01:00 60

08:00:00 30

08:00:02 2

08:03:00 10

Sample Output:

8.2

 

直接模拟

 

代码：

一开始想差了，改得很挫，有空写过……

#include <iostream>
#include <vector>
#include <queue>
#include <algorithm>
using namespace std;

const int MAX=0x7fffffff;	//最大时间限制

struct cus	//客户结构
{
	int time;	//到达时间，以秒计
	int ser_time;	//服务时间,以秒计
};

int To_second(int hour,int min,int sec);	//将时间转换为秒
int Get_time();		//获取时间，并调用To_second()转换为秒
bool cm(const cus &c1,const cus &c2);	//比较客户的到达时间，用于排序
void Put_time(long long time,int n1);	//输出平均等待时间，输入为总等待时间和有效人数

int main()
{
	int n,k,n1;	//n,k,有效人数n1
	cin>>n>>k;
	int i;

	deque<cus> custom;	//客户队列
	cus cus_temp;
	for(i=0;i<n;i++)
	{
		cus_temp.time=Get_time();
		cin>>cus_temp.ser_time;
		cus_temp.ser_time*=60;
		if(cus_temp.time<=61200)	//17:00前的客户
			custom.push_back(cus_temp);
	}

	long long time=28800,total_time=0;	//初始时间8:00，总等待时间
	if(custom.empty())
	{
		cout<<0.0;
		return 0;
	}
	else
	{
		n1=custom.size();	//统计有效人数
		sort(custom.begin(),custom.end(),cm);
		for(i=0;i<n1;i++)	//处理早到的人
		{
			if(custom[i].time<28800)
			{
				total_time+=(28800-custom[i].time);
				custom[i].time=28800;
			}
		}
	}

	queue<cus> window[100];	//窗口……由于只有1个，其实不需要队列的
	int s_time,a_time;	//最小的服务时间，最早的到达时间（仅统计比当前时间晚的，用于处理所有窗口中的客户都为空后来客户的情况）……这个是多余的
	for(i=0;i<k;i++)	//压入各窗口第一个
	{
		window[i].push(custom.front());
		custom.pop_front();
		if(custom.empty())
			break;
	}
	if(i<k)	//如果人数少于窗口，结束
		Put_time(total_time,n1);
	else
	{
		while(!custom.empty())
		{
			s_time=MAX;
			a_time=MAX;
			for(i=0;i<k;i++)
			{
				if(window[i].front().time<=time)	//获取已经服务中最早结束的
				{
					if(window[i].front().ser_time<s_time)
						s_time=window[i].front().ser_time;
				}
				else if(window[i].front().time-time+window[i].front().ser_time<s_time)	//考虑后来的是否先结束的情况
				{
					s_time=window[i].front().time-time+window[i].front().ser_time;
				}
				else if(window[i].front().time<a_time)	//获取最到的来到时间（当前时间未到的人中）……这个是多余的
					a_time=window[i].front().time;
			}
			if(s_time<MAX)	//更改时间
				time+=s_time;
			else	//更改时间（两个时间点间没有服务对象）……多余的
			{
				time=a_time;
				continue;
			}

			for(i=0;i<k;i++)	//扫描窗口，处理时间
			{
				if(window[i].front().time<time)	//在时间段内被服务的，需要减服务时间
				{
					if(time-s_time>=window[i].front().time)	//在时间段之前来的
						window[i].front().ser_time-=s_time;
					else	//在时间段中来的
						window[i].front().ser_time-=time-window[i].front().time;
				}
				if(window[i].front().ser_time==0)	//有窗口空闲
				{
					window[i].pop();
					if(custom.empty())	//都已经服务到，结束
					{
						Put_time(total_time,n1);
						return 0;
					}
					else	//压入时间
					{
						if(time>custom.front().time)	//对已经在黄线外等待的客户计算等待，！！！对假想的将来的客户仅做压入处理
							total_time+=time-custom.front().time;
						window[i].push(custom.front());
						custom.pop_front();
					}
				}
			}
		}
		Put_time(total_time,n1);
	}

	return 0;
}

int To_second(int hour,int min,int sec)
{
	return hour*3600+min*60+sec;
}

int Get_time()
{
	int hour,min,sec;
	cin>>hour;
	cin.get();
	cin>>min;
	cin.get();
	cin>>sec;
	return To_second(hour,min,sec);
}

bool cm(const cus &c1,const cus &c2)
{
	return c1.time<c2.time;
}

void Put_time(long long time,int n1)
{
	double t=time/(60.0*n1);
	cout<<fixed;
	cout.precision(1);
	cout<<t;
}