Hdu 1022 Train Problem I 栈

Train Problem I

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 51413    Accepted Submission(s): 19341

Problem Description
As the new term comes, the Ignatius Train Station is very busy nowadays. A lot of student want to get back to school by train(because the trains in the Ignatius Train Station is the fastest all over the world ^v^). But here comes a problem, there is only one railway where all the trains stop. So all the trains come in from one side and get out from the other side. For this problem, if train A gets into the railway first, and then train B gets into the railway before train A leaves, train A can't leave until train B leaves. The pictures below figure out the problem. Now the problem for you is, there are at most 9 trains in the station, all the trains has an ID(numbered from 1 to n), the trains get into the railway in an order O1, your task is to determine whether the trains can get out in an order O2.

Input
The input contains several test cases. Each test case consists of an integer, the number of trains, and two strings, the order of the trains come in:O1, and the order of the trains leave:O2. The input is terminated by the end of file. More details in the Sample Input.

Output
The output contains a string "No." if you can't exchange O2 to O1, or you should output a line contains "Yes.", and then output your way in exchanging the order(you should output "in" for a train getting into the railway, and "out" for a train getting out of the railway). Print a line contains "FINISH" after each test case. More details in the Sample Output.

Sample Input
3 123 321
3 123 312
 

Sample Output
Yes.
in
in
in
out
out
out
FINISH
No.
FINISH

HintHint 
For the first Sample Input, we let train 1 get in, then train 2 and train 3.
So now train 3 is at the top of the railway, so train 3 can leave first, then train 2 and train 1.
In the second Sample input, we should let train 3 leave first, so we have to let train 1 get in, then train 2 and train 3.
Now we can let train 3 leave.
But after that we can't let train 1 leave before train 2, because train 2 is at the top of the railway at the moment.
So we output "No.".

 题解：题目要求可转化为能否将s1元素进栈，然后输出为s2的排列形式，所以我们在使s1元素进栈的时候和s2的元素匹配，并记录顺序，若最后s1的全部输出完，那么就成立；

 

#include<iostream>
#include<stack>
#include<string.h>
using namespace std;
char s[55],ss[55];
bool in[11111];
int main()
{
        int n;
        while(~scanf("%d %s%s",&n,s,ss)){
                stack<char>p;
                int j=0,k=0;
                for(int i=0;s[i];i++){
                        p.push(s[i]);
                        in[k++]=1;
                        while(!p.empty()&&p.top()==ss[j]){
                                //将可以与ss匹配的出栈,加入与ss一样的队形
                                in[k++]=0;//记录步骤
                                p.pop();
                                j++;
                        }
                }
                if(p.empty()){
                        printf("Yes.
");
                        for(int i=0;i<k;i++)
                                printf("%s
",in[i]?"in":"out");
                }else{
                        printf("No.
" );
                }
                printf("FINISH
");
        }
        return 0;
}