1405_Tanning Salon

Tan Your Hide, Inc., owns several coin-operated tanning salons. Research has shown that if a customer arrives and there are no beds available, the customer will turn around and leave, thus costing the company a sale. Your task is to write a program that
tells the company how many customers left without tanning.

The input consists of data for one or more salons, followed by a line containing the number 0 that signals the end of the input. Data for each salon is a single line containing a positive integer, representing the number of tanning beds in the salon, followed
by a space, followed by a sequence of uppercase letters. Letters in the sequence occur in pairs. The first occurrence indicates the arrival of a customer, the second indicates the departure of that same customer. No letter will occur in more than one pair.
Customers who leave without tanning always depart before customers who are currently tanning. There are at most 20 beds per salon.

For each salon, output a sentence telling how many customers, if any, walked away. Use the exact format shown below.

Sample Input

2 ABBAJJKZKZ

3 GACCBDDBAGEE

3 GACCBGDDBAEE

1 ABCBCA

0



Sample Output

All customers tanned successfully.

1 customer(s) walked away.

All customers tanned successfully.

2 customer(s) walked away.

Source: Mid-Central USA 2002

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//和操作系统中的临界资源相似

#include<iostream>

#include<string>

using namespace std;

int main()

{

int num;

string cus;

string l_n;//保存第一次进来但是没有床位的字符

bool flag_1;

bool flag_2;

while(cin>>num&&num)

{

l_n.clear();

cin>>cus;

--num;

for(int i=1;i!=cus.size();i++)//从第二个字符开始与前面的字符分别匹配。成功->查找l_n,没有此字符，表明拥有资源者退出，++num;失败->表明第一次来->查num->若num>0,说明有资源，--num;若num=0;说明没有资源，将字符移入l_n

{

flag_1=false;//这个位置很重要

for(int j=0;j!=i;j++)

{

if(cus[i]==cus[j])

{

flag_2=false;//这个位置很重要

flag_1=true;

for(int k=0;k!=l_n.size();k++)

if(cus[j]==l_n[k])

{

flag_2=true;

break;

}

if(flag_2==false)

++num;

break;

}

}

if(flag_1==false)

if(num==0)

l_n+=cus[i];

else

--num;

}

if(l_n.size()==0)

cout<<"All customers tanned successfully."<<endl;

else

cout<<l_n.size()<<" customer(s) walked away."<<endl;

}

return 0;

}