F -- HDU 1022 Train Problem I

Train Problem I

Time Limit: 1000 MS Memory Limit: 32768 KB

64-bit integer IO format: %I64d , %I64u Java class name: Main

[Submit] [Status] [Discuss]

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

Hint

Hint

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.".


题目大意：
有N辆火车，以序列1方式进站，判断是否能以序列2方式出栈。进站不一定是一次性进入，也就是说中途可以出站。

解题分析：
先把两个字符串存起来，然后先进栈，若遇到出栈的信息且要出的那辆车刚好在栈顶就可以出。否则就进栈

代码：

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <stack>
 4 using namespace std;
 5 char a[100005];
 6 char b[100005];
 7 int c[100005];
 8 int main(){
 9     int n;
10     stack<char>s;       //注意创建栈的位置，如果不是每次都重新创建，则需在操作之前把栈清空
11     while(~scanf("%d",&n)){
12             //stack<char>s; //若每次都重新创建则不需要清空栈
13             while(!s.empty()) s.pop();  //清空栈
14             scanf("%s %s",a,b);
15             int i=0;    //i 是进站火车的指针
16             int j=0;    //j 是出站火车的指针 
17             int k=0;    //k 是存放 in,out数组 c 的指针
18         while(i<n){ 
19             if(s.empty()||s.top()!=b[i]&&j<n){
20                 s.push(a[j++]);
21                 c[k++]=1;   //1为进站 对应 in
22             }
23             else if(s.top()==b[i]){
24                 s.pop();
25                 c[k++]=0;   //0 为火车出站 对应 out
26                 i++;
27             }
28             else break;
29         }
30         if(s.empty()){
31             printf("Yes.\n");
32             for(i=0;i<k;i++){
33                 if(c[i]==1) printf("in\n");
34                 else printf("out\n");
35             }
36             printf("FINISH\n");
37         }
38         else printf("No.\nFINISH\n");
39     }
40     return 0;
41 }