1014. Waiting in Line (30)

Posted 2020-10-09 gaoren

Suppose a bank has N windows open for service. There is a yellow line in front of the windows which devides the waiting area into two parts. The rules for the customers to wait in line are:

• The space inside the yellow line in front of each window is enough to contain a line with M customers. Hence when all the N lines are full, all the customers after (and including) the (NM+1)st one will have to wait in a line behind the yellow line.
• Each customer will choose the shortest line to wait in when crossing the yellow line. If there are two or more lines with the same length, the customer will always choose the window with the smallest number.
• Customer[i] will take T[i] minutes to have his/her transaction processed.
• The first N customers are assumed to be served at 8:00am.

Now given the processing time of each customer, you are supposed to tell the exact time at which a customer has his/her business done.

For example, suppose that a bank has 2 windows and each window may have 2 custmers waiting inside the yellow line. There are 5 customers waiting with transactions taking 1, 2, 6, 4 and 3 minutes, respectively. At 08:00 in the morning, customer₁ is served at window₁ while customer₂ is served at window₂. Customer₃ will wait in front of window₁ and customer₄ will wait in front of window₂. Customer₅ will wait behind the yellow line.

At 08:01, customer₁ is done and customer₅ enters the line in front of window₁ since that line seems shorter now. Customer₂ will leave at 08:02, customer₄ at 08:06, customer₃ at 08:07, and finally customer₅ at 08:10.

Input

Each input file contains one test case. Each case starts with a line containing 4 positive integers: N (<=20, number of windows), M (<=10, the maximum capacity of each line inside the yellow line), K (<=1000, number of customers), and Q (<=1000, number of customer queries).

The next line contains K positive integers, which are the processing time of the K customers.

The last line contains Q positive integers, which represent the customers who are asking about the time they can have their transactions done. The customers are numbered from 1 to K.

Output

For each of the Q customers, print in one line the time at which his/her transaction is finished, in the format HH:MM where HH is in [08, 17] and MM is in [00, 59]. Note that since the bank is closed everyday after 17:00, for those customers who cannot be served before 17:00, you must output "Sorry" instead.

Sample Input

2 2 7 5
1 2 6 4 3 534 2
3 4 5 6 7

Sample Output

08:07
08:06
08:10
17:00
Sorry

本题主要考的是优先队列的使用。首先在优先队列里存储n*m个客户的结束时间end_time及开始时间start_time，并记录各自属于哪个窗口。额外由
line_end_time[n]数组记录每个窗口的在黄线内最后的处理时间T。当处理第n*m+1的客户C时，由优先队列取出最早结束的客户c1，此时客户C的
开始时间即为c1所在窗口的T，结束时间为开始时间加上C的处理时间，并更新它所在窗口的最后处理时间。

#include<iostream>
#include<stdio.h>
#include<algorithm>
#include<queue>
#include <vector>
#include<string.h>
using namespace std;
struct Customer{
	int window_id;
	int start_time;
	int process_time;
	int end_time;
	bool operator < (const Customer tmp) const {
		if( end_time == tmp.end_time){
			return window_id > tmp.window_id;
		} else{
			return end_time > tmp.end_time;
		}
	}
};
const int max_customer = 1002;
struct Customer customer[max_customer];
priority_queue<Customer>con_queue_line;
int n,m,k,q;
int query[max_customer];
int line_end_time[21];
int main(){
	scanf("%d%d%d%d",&n,&m,&k,&q);
	int i,j;
	for(i=1;i<=k;i++){
		scanf("%d",&customer[i].process_time);
		customer[i].end_time =0;
		customer[i].start_time =0;
	}
	for(i=1;i<=q;i++){
		scanf("%d",&query[i]);
	}
	memset(line_end_time,0,sizeof(line_end_time));
	int flag=0;
	Customer c;
	for(i=1;i<=m && flag<k; i++){
		for(j=0;j<n && flag<k; j++){
			flag ++;
			c.start_time = line_end_time[j];
			c.window_id = j;
			c.end_time = c.start_time + customer[flag].process_time;
			line_end_time[j] = c.start_time + customer[flag].process_time;
			customer[flag].window_id = c.window_id;
			customer[flag].end_time = c.end_time;
			customer[flag].start_time = c.start_time;
			con_queue_line.push(c);
		}
	}
	Customer tmp;
	for(i=flag+1;i<=k;i++){
		c = con_queue_line.top();
		con_queue_line.pop();		
		tmp.start_time = line_end_time[c.window_id];
		tmp.window_id = c.window_id;
		tmp.end_time = customer[i].process_time + tmp.start_time;
		line_end_time[c.window_id] = customer[i].process_time + tmp.start_time;
		customer[i].end_time = tmp.end_time;
		customer[i].start_time = tmp.start_time;
		customer[i].window_id = tmp.window_id;
		con_queue_line.push(tmp);
	}
	int c_id;
	int time = (17-8)*60;
	for(i = 1;i<=q;i++){
		c_id = query[i];
		if(customer[c_id].start_time >= time){
			printf("Sorry\n");
		} else {
			int h = customer[c_id].end_time/60;
			int m = customer[c_id].end_time%60;
			printf("%02d:%02d\n",h+8,m);
		}
	}
	return 0;
}