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

#include <stdio.h>
#include <iostream>
#include <stack>
using namespace std;
const int maxn = 1e4;
int n,a[maxn];
int main(){
    while(scanf("%d", &n) == 1){
        string str1, str2, str3[maxn];
        cin>>str1>>str2;
        stack<char> s;
        int A = 0,B = 0, t = 0, flag = 1;
        while(B < n){
            if(str1[A] == str2[B]) str3[t++] = "in", str3[t++] = "out",A++,B++;
            else if(!s.empty() && s.top() == str2[B]) str3[t++] = "out",s.pop(), B++;
            else if(A < n) s.push(str1[A++]), str3[t++] = "in";
            else { flag = 0; break; }
        }
        if(flag){
            cout<<"Yes."<<endl;
            for(int i = 0; i < t; i++){
                cout<<str3[i]<<endl;
            }
        }
        else cout<<"No."<<endl;
        cout<<"FINISH"<<endl;
    }
    return 0;
}

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