SDOTOJ2088 refresh的停车场

2 6
Add 18353364208
Add 18353365550
Add 18353365558
Add 18353365559
Del
Out

18353365558
18353364208

#include<iostream>
#include<algorithm>
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<string>
#include<stack>
#include<queue>

using namespace std;

string a[2000021],b[2000021];
int n,m;

int main()
{
    while(cin >> n >> m)
    {
        int flag = 0;
        string str,num;
        int h = 0,k1 = 0,k2 = 0;
        for(int i=0; i<m; i++)
        {
            cin >> str;
            if(str == "Add")
            {
                cin >> num;
                if(h<n)
                {
                    a[++h] = num;
                }
                else
                {
                    b[++k2] = num;
                }

            }
            else if(str == "Del")
            {
                if(h<=0)
                {
                    flag = 1;
                }
                else if(k2 > k1)
                {

                    a[h] = b[++k1];
                }
                else if(k2<=k1)
                {
                    h--;
                }

            }
            else if(str == "Out")
            {
                if(k2 <= k1)
                {
                    flag = 1;
                }
                else
                {
                    k1++;
                }

            }

        }
        if(h>0 && flag == 0)
        {
            while(h>0)
            {
                cout << a[h] << endl;
                h--;
            }
        }
        else if(flag == 1)
        {
            cout << "Error" << endl;
        }

    }
    return 0;
}

#include<iostream>
#include<algorithm>
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<string>
#include<stack>
#include<queue>

using namespace std;

int n,m;

int main()
{
    while(cin >> n >> m)
    {
        stack<string>a;
        queue<string>b;
        int flag = 0;
        string str,num;
        for(int i=0; i<m; i++)
        {
            cin >> str;
            if(str == "Add")
            {
                cin >> num;
                if(a.size() == n)
                {
                    b.push(num);
                }
                else
                {
                    a.push(num);
                }
            }
            else if(str == "Del")
            {

                if(a.empty())
                {
                    flag = 1;
                }
                else
                {
                    a.pop();
                    if(!b.empty())
                    {
                        a.push(b.front());
                        b.pop();
                    }
                }
            }
            else if(str == "Out")
            {

                if(b.empty())
                {
                    flag = 1;
                }
                else
                {
                    b.pop();
                }
            }
            // printf("h = %d    k1 = %d   k2 = %d\n",h,k1,k2);
        }

        if(flag == 1)
        {
            cout << "Error" << endl;
        }
        else
        {
            while(!a.empty())
            {
                cout << a.top() << endl;
                a.pop();
            }

        }
    }
    return 0;
}