ACboy needs your help again!

Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 4429    Accepted Submission(s): 2260

Problem Description

ACboy was kidnapped!!
he miss his mother very much and is very scare now.You can‘t image how dark the room he was put into is, so poor :(.
As a smart ACMer, you want to get ACboy out of the monster‘s labyrinth.But when you arrive at the gate of the maze, the monste say :" I have heard that you are very clever, but if can‘t solve my problems, you will die with ACboy."
The problems of the monster is shown on the wall:
Each problem‘s first line is a integer N(the number of commands), and a word "FIFO" or "FILO".(you are very happy because you know "FIFO" stands for "First In First Out", and "FILO" means "First In Last Out").
and the following N lines, each line is "IN M" or "OUT", (M represent a integer).
and the answer of a problem is a passowrd of a door, so if you want to rescue ACboy, answer the problem carefully!

Input

The input contains multiple test cases.
The first line has one integer,represent the number oftest cases.
And the input of each subproblem are described above.

Output

For each command "OUT", you should output a integer depend on the word is "FIFO" or "FILO", or a word "None" if you don‘t have any integer.

Sample Input

4

4 FIFO

IN 1

IN 2

OUT

OUT

4 FILO

IN 1

IN 2

OUT

OUT

5 FIFO

IN 1

IN 2

OUT

OUT

OUT

5 FILO

IN 1

IN 2

OUT

IN 3

OUT

3

Sample Output

1

2

2

1

1

2

None

2

3

这个题大意就是：FIFO代表是先输入的数先输出，FILO代表的是先输入的数后输出。没有数据就输出None！

很容易想到用栈和队列来解决问题。

 1 #include<stdio.h>
 2 #include<string.h>
 3 #include<stack> 4 #include<queue> 5 using namespace std;
 6 char s1[10],s2[10];
 7 int main()
 8 {
 9     int n,a,b;
10
11     scanf("%d",&n);
12     while(n--)
13     {
14         queue<int>s;//定义一个队列
15         while(!s.empty())
16         s.pop();
17         stack<int>r;//定义一个栈
18         while(!r.empty())19         r.pop();//一定要每次都要清空队列，要不然各种WA我也是醉了！
20         scanf("%d %s",&a,s1);
21         getchar();//注意吸收回车
22         if(strcmp(s1,"FIFO")==0)
23         {
24             while(a--)
25             {
26                 scanf("%s",s2);
27                 if(strcmp(s2,"IN")==0)
28                 {
29                     scanf("%d",&b);
30                     getchar();
31                     s.push(b);
32                  }
33                  else if(strcmp(s2,"OUT")==0)
34                  {
35                      if(s.empty())
36                      printf("None\n");
37                      else
38                      {
39                          printf("%d\n",s.front());//输出队首元素
40                          s.pop();
41                      }
42
43                  }
44             }
45         }
46         else if(strcmp(s1,"FILO")==0)
47         {
48             while(a--)
49             {
50                 scanf("%s",s2);
51                 if(strcmp(s2,"IN")==0)
52                 {
53                     scanf("%d",&b);
54                     getchar();
55                     r.push(b);
56                  }
57                  else if(strcmp(s2,"OUT")==0)
58                  {
59                      if(r.empty())
60                      printf("None\n");
61                      else
62                      {
63                          printf("%d\n",r.top());//输出栈顶元素
64                          r.pop();
65                      }
66
67                  }
68             }
69         }
70     }
71     return 0;
72 }