wenbao与stack

栈

stack又叫后进先出即 LIFO（last in first out）

火车进站经典问题

 1 #include <stdio.h>
 2 #include <iostream>
 3 #include <stack>
 4 using namespace std;
 5 const int maxn = 1e4;
 6 int n,a[maxn];
 7 int main(){
 8     while(scanf("%d", &n) == 1){
 9         string str1, str2, str3[maxn];
10         cin>>str1>>str2;
11         stack<char> s;
12         int A = 0,B = 0, t = 0, flag = 1;
13         while(B < n){
14             if(str1[A] == str2[B]) str3[t++] = "in", str3[t++] = "out",A++,B++;
15             else if(!s.empty() && s.top() == str2[B]) str3[t++] = "out",s.pop(), B++;
16             else if(A < n) s.push(str1[A++]), str3[t++] = "in";
17             else { flag = 0; break; }
18         }
19         if(flag){
20             cout<<"Yes."<<endl;
21             for(int i = 0; i < t; i++){
22                 cout<<str3[i]<<endl;
23             }
24         }
25         else cout<<"No."<<endl;
26         cout<<"FINISH"<<endl;
27     }
28     return 0;
29 }

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