A - ACboy needs your help again!

最新推荐文章于 2019-10-29 10:18:11 发布

原创最新推荐文章于 2019-10-29 10:18:11 发布 · 350 阅读

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本文通过一个有趣的背景故事介绍并实现了队列(queue)与栈(stack)这两种基本的数据结构。通过解决一系列问题，展示了如何使用C++来操作这两种数据结构，并提供了完整的代码实现。

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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

Sample Output

分析：本题是queue(队列）和stack（栈）的基本用法，注意题意：有out而数据为空时输出的是None;

代码：

#include<cstdio>
#include<cmath>
#include<cstring>
#include<algorithm>
#include<stack>
#include<queue>
using namespace std;
char s[5];
int a;
int Que_ue(int n)
{
	queue<int >que;
	while(n--)
	{
		scanf("%s",s);
		if(strcmp(s,"IN")==0)
		{
			scanf("%d",&a);
			que.push(a); 
		}
		else if(strcmp(s,"OUT")==0)
		{
			if(que.empty() )
			printf("None\n");
		    else {
		    	printf("%d\n",que.front());
		    	que.pop() ;
			}
		}
	}
}
int Stack_k(int n)
{
	stack<int >sta;
	while(n--)
	{
		scanf("%s",s);
		if(strcmp(s,"IN")==0)
		{
			scanf("%d",&a);
		    sta.push(a);  
		}
		else if(strcmp(s,"OUT")==0)
		{
			if(sta.empty() )
			printf("None\n");
		    else {
		      printf("%d\n",sta.top() );
		    	sta.pop() ;
	        }
       }
   }
}
int main()
{
	int T,n;
	char str[10];
	scanf("%d",&T);
	while(T--)
	{
		scanf("%d%s",&n,str);
		if(strcmp(str,"FIFO")==0)
		Que_ue(n);
		else Stack_k(n);
	}
	return 0;
 }