SGU 271 Book Pile

There is a pile of N books on the table. Two types of operations are performed over this pile: 
- a book is added to the top of the pile, 
- top K books are rotated. If there are less than K books on the table, the whole pile is rotated. 
First operation is denoted as ADD(S) where S is the name of the book, and the second operations is denoted as ROTATE. 
The maximum number of books is no more than 40000. All book names are non-empty sequences of no more than 3 capital Latin letters. The names of the books can be non-unique.

Input

The first line of input file contains 3 integer numbers N, M, K (0 <= N <= 40000; 0 <= M <= 100000; 0 <= K <= 40000). The following N lines are the names of the books in the pile before performing any operations. The book names are given in order from top book to bottom. Each of the following M lines contains the operation description. 

Output

Output the sequence of books names in the pile after performing all operations. First line corresponds to the top book. 

Sample test(s)

Input

2 3 2 
A 
B 
ADD(C) 
ROTATE 
ADD(D) 

Output

D 
A 
C 
B 

 

题意 

一堆书，进行两个操作，一个是再堆上一本书，另一个是把上面k本书的顺序调转。现进行了m次操作，问书堆最后的情况。

 

分析 

两种操作都只与上面k本书有关系，可以使用双端队列来模拟，至于调转操作就是选择堆书的一端不同。

 

#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<algorithm>
#include<cstring>
#include <queue>
#include <vector>
#include<bitset>
#include<map>
#include<deque>
using namespace std;
typedef long long LL;
const int maxn = 1e5+150;
const int mod = 77200211+233;
typedef pair<int,int> pii;
#define X first
#define Y second
#define pb push_back
#define mp make_pair
#define ms(a,b) memset(a,b,sizeof(a))
const int inf = 0x3f3f3f3f;
#define lson l,m,2*rt
#define rson m+1,r,2*rt+1


int main(){
//    freopen("in.txt","r",stdin);
    int n,m,k;
    scanf("%d%d%d",&n,&m,&k);
    deque<string>q1;
    deque<string>q2;
    int dir=1;
    for(int i=0;i<n;i++){
        char str[15];
        scanf("%s",str);
        if(q1.size()>=k) q2.push_back(string(str));
        else q1.push_back(string(str));
    }
    for(int i=0;i<m;i++){
        char str[50];
        scanf("%s",str);
        if(str[0]=='A'){
            string s="";
            int len=strlen(str);
            int ok=0;
            for(int j=0;j<len;j++){
                if(str[j]=='(') ok=1;
                else if(str[j]==')') ok=0;
                else if(ok) s+=str[j];
            }
            if(dir) q1.push_front(s);
            else q1.push_back(s);

            if(q1.size()>k){
                if(dir){
                    q2.push_front(q1.back());
                    q1.pop_back();
                }else{
                    q2.push_front(q1.front());
                    q1.pop_front();
                }
            }
        }else dir = !dir;
    }
    if(dir){
        while(!q1.empty()){
            cout<<q1.front()<<endl;
            q1.pop_front();
        }
    }else{
        while(!q1.empty()){
            cout<<q1.back()<<endl;
            q1.pop_back();
        }
    }
    while(!q2.empty()){
        cout<<q2.front()<<endl;
        q2.pop_front();
    }
    return 0;
}