HDU1702 ACboy needs your help again!(队列和栈)

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题目:

ACboy needs your help again!

**Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 6094    Accepted Submission(s): 3197
**
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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!

 

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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.

 

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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.

 

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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
  
  

 

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Sample Output

  
  

   
   1
2
2
1
1
2
None
2
3
  
  

 

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Source

2007省赛集训队练习赛(1)

代码:

#include <stdio.h>
#include <stack>
#include <cstring>
#include <queue>
using namespace std;
int main()
{
    int t;
    scanf("%d",&t);//数据的组数
    while(t--)
    {
        int n;
        queue<int> q;//先声明一个队列和一个栈
        stack<int> s;
        char str[10];
        scanf("%d %s",&n,str);
        if(strcmp(str,"FIFO")==0)//判断输入要求的是队列
        {
            while(n--)//指令的组数
            {
                char zl[10];
                int x;
                scanf("%s",zl);
                if(strcmp(zl,"IN")==0)
                {
                    scanf("%d",&x);
                    q.push(x);//如果是输入的指令,就把输入的值加入队列
                }
                else if(strcmp(zl,"OUT")==0)//如果是出的指令
                {
                    if(!q.empty())//当队列非空时
                    {
                        printf("%d\n",q.front());//打印队首,并抛弃队首元素
                        q.pop();
                    }
                    else
                    {
                        printf("None\n");
                    }
                }
            }
        }
        else if(strcmp(str,"FILO")==0)//判断输入要求的是栈
        {
            while(n--)//命令的组数
            {
                char zl[10];
                int x;
                scanf("%s",zl);
                if(strcmp(zl,"IN")==0)
                {
                    scanf("%d",&x);
                    s.push(x);//如果是输入的指令,就把输入的值加入栈
                }
                else if(strcmp(zl,"OUT")==0)
                {
                    if(!s.empty())//当栈非空时
                    {
                        printf("%d\n",s.top());//打印栈顶元素,并出栈
                        s.pop();
                    }
                    else
                    {
                        printf("None\n");
                    }
                }
            }
        }

    }
    return 0;
}

PS:队列和栈的一道很简单的练习题,帮助理解概念
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