백준 10866

#include <iostream>
#include <vector>
#include <string>

using namespace std;

class Deque
{
private:
	int deque[10001] = { 0, };
	int first = 0, end = 0;

public:
	Deque()
	{
		
	}
	~Deque()
	{
		
	}

public:
	void Push_front(int num)
	{		
		if (end != 0)
		{
			for (int i = end; i > 0; --i)
			{
				deque[i] = deque[i - 1];
			}
		}
		deque[first] = num;
		end++;
		
	}
	void Push_back(int num)
	{
		deque[end] = num;
		end++;
	}
	int Pop_front()
	{
		if (empty())
		{
			return -1;
		}
		int output = deque[first];
		
		
		for (int i = 0; i <= end; ++i)
		{
			deque[i] = deque[i + 1];

		}
		end--;
		return output;
	}
	int Pop_back()
	{
		if (empty())
		{
			return -1;
		}
		end--;
		int output = deque[end];
		
		return output;
	}
	int Size()
	{
		return end;
	}
	bool empty()
	{
		if (Size() == 0)
		{
			return true;
		}
		else
		{
			return false;
		}
	}
	int front()
	{
		if (empty())
		{
			return -1;
		}
		return deque[first];
	}
	int back()
	{
		if (empty())
		{
			return -1;
		}
		int a = end - 1;
		return deque[a];
	}

};

int main(void)
{
	ios::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);

	int input = 0;

	cin >> input;

	Deque q;

	for (int i = 0; i < input; ++i)
	{
		string order;
		cin >> order;

		if (order == "push_front")
		{
			int num = 0;
			cin >> num;
			q.Push_front(num);
		}
		else if (order == "push_back")
		{
			int num = 0;
			cin >> num;
			q.Push_back(num);
		}
		else if (order == "pop_front")
		{
			cout << q.Pop_front() << "\n";
		}
		else if (order == "pop_back")
		{
			cout << q.Pop_back() << "\n";
		}
		else if (order == "size")
		{
			cout << q.Size() << "\n";
		}
		else if (order == "empty")
		{
			cout << q.empty() << "\n";
		}
		else if (order == "front")
		{
			cout << q.front() << "\n";
		}
		else if (order == "back")
		{
			cout << q.back() << "\n";
		}


	}



	return 0;
}