bnuoj 29373 Key Logger（模拟双向队列）

http://www.bnuoj.com/bnuoj/problem_show.php?pid=29373

【题意】：模拟光标输入

【题解】：用双向列表模拟实现，这里用其他模拟会超时，注意内存的释放

【code】：

 #include <iostream>
 #include <stdio.h>
 #include <math.h>
 #include <algorithm>
 #include <list>
 #include <string>
 #include <string.h>

 using namespace std;

 struct Nod
 {
     char ch;
     Nod * second;
     Nod * first;
     Nod()
     {
         second=NULL;
         first=NULL;
         ch=;
     }
 };
 Nod * head,*tail,*now,*temp;

 char str[];

 int main()
 {
     int t,cas=;
     scanf("%d",&t);
     while(t--)
     {
         int i;
         scanf("%s",str);
         int len = strlen(str);
         head = new Nod;
         tail = new Nod;
         head->second = tail;
         tail->first = head;
         now = head;
         int pos = ;
         for(i=;i<len;i++)
         {
             char ch = str[i];
             if(ch=='<')
             {
                 if(now!=head)
                 {
                     now = now->first;
                   //  cout<<" sdfsd"<<endl;
                 }
             }
             else if(ch=='>')
             {
                 if(now->second!=tail)
                 {
                     now = now->second;
                 }
             }
             else if(ch=='-')
             {
                 if(now!=head)
                 {
                     now->first->second = now->second;
                     now->second->first = now->first;
                     temp = now;
                     free(temp);
                     now = now->first;
                 }
             }
             else
             {
                 temp = new Nod;
                 temp->ch = ch;
                 now->second->first = temp;
                 temp->second =now->second;
                 now->second = temp;
                 temp->first = now;
                 now = now->second;
             }
         }
         now = head->second;
         printf("Case %d: ",cas++);
         while(now!=tail)
         {
             printf("%c",now->ch);
             now = now->second;
             free(now->first);
         }
         free(now);
         putchar();
     }
     return ;
 }