[Silver IV] 덱 - 10866

[문제 위치]

https://www.acmicpc.net/problem/10866

[문제 풀이]

자료구조 큐를 이용하여 덱을 구현하는 문제이다.

#include <iostream>
#include <deque>
#include <string>

using namespace std;

int main(int argc, char**argv) {

	ios::sync_with_stdio(0);
	cin.tie(0);
		
	deque<int> DQ;
	int N;
	
	cin >> N;
	
	while(N--){
		string str;
		cin >> str;
		
		if(str=="push_front"){
			int X;
			cin >> X;
			DQ.push_front(X);
		}
		
		else if(str=="push_back"){
			int X;
			cin >> X;
			DQ.push_back(X);
		}
		
		else if(str=="pop_front"){
			if(!DQ.empty()){
				cout << DQ.front() <<"\n";
				DQ.pop_front();
			}
			else
				cout << "-1\n";
		}
		
		else if(str=="pop_back"){
			if(!DQ.empty()){
				cout << DQ.back()<<"\n";
				DQ.pop_back();
			}
			else
				cout << "-1\n";
		}
		
		else if(str=="size"){
			cout << DQ.size() <<"\n";
		}
		
		else if(str=="empty"){
			cout << DQ.empty() <<"\n";
		}
		
		else if(str=="front"){
			if(!DQ.empty()){
				cout << DQ.front() <<"\n";
			}
			else
				cout << "-1\n";
		}
		
		else if(str=="back"){
			if(!DQ.empty()){
				cout << DQ.back() <<"\n";
			}
			else
				cout << "-1\n";
		}
	}		
	return 0;
}