[BOJ] 10866 덱

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

10866번: 덱

using System;
using System.IO;
using System.Runtime.InteropServices;
using System.Text;

namespace Deque
{
    internal class Program
    {
       static int[] deque = new int[10001];
       static int cnt;
       static bool isEmpty;
       public static int front= deque.Length / 2, back= (deque.Length / 2)+1;
        public static void Main(string[] args)
        {
            StreamReader sr = new StreamReader(new BufferedStream(Console.OpenStandardInput()));
            StreamWriter sw = new StreamWriter(new BufferedStream(Console.OpenStandardOutput()));
            StringBuilder sb = new StringBuilder();
            int rep = int.Parse(sr.ReadLine());
            for (var i = 0; i < rep; i++)
            {
                string[] input = sr.ReadLine().Split();
                switch (input[0])
                {
                    case "push_front":
                        pushFront(int.Parse(input[1]));
                        break;
                    case "push_back":
                        pushBack(int.Parse(input[1]));
                        break;
                    case "pop_front":
                        sb.AppendLine(popFront().ToString());
                        break;
                    case "pop_back":
                        sb.AppendLine(popBack().ToString());
                        break;
                    case "size":
                        sb.AppendLine(size().ToString());
                        break;
                    case "empty":
                        sb.AppendLine(empty().ToString());
                        break;
                    case "front":
                        sb.AppendLine(Front().ToString());
                        break;
                    case "back":
                        sb.AppendLine(Back().ToString());
                        break;
                }
            }
            sw.WriteLine(sb.ToString());
            sw.Close();
            sr.Close();
        }

        static void pushFront(int x)
        {
            deque[front] = x;
            cnt++;
            if (front == 0)
            {
                front = deque.Length - 1;
            }
            else
            {
                front--;    
            }
            
        }

        static void pushBack(int x)
        {
            deque[back] = x;
            cnt++;
            if (back == deque.Length - 1)
            {
                back = 0;
            }
            else
            {
                back++;
            }
        }

        static int popFront()
        {
            if (cnt == 0)
            {
                return -1;
            }
            int num = deque[front + 1];
            cnt--;
            front++;
            return num;
        }

        static int popBack()
        {
            if (cnt == 0)
            {
                return -1;
            }
            int num = deque[back - 1];
            cnt--;
            back--;
            return num;
        }
        static int size()
        {
            return cnt;
        }
        static int empty()
        {
            if (cnt > 0)
            {
                return 0;
            }
            return 1;
        }
        static int Front()
        {
            if (cnt == 0)
            {
                return -1;
            }

            if (front == deque.Length - 1)
            {
                return deque[0];
            }
            return deque[front + 1];
        }
        private static int Back()
        {
            if (cnt == 0)
            {
                return -1;
            }
            if (back == 0)
            {
                return deque[deque.Length - 1];
            }
            return deque[back - 1];
        }
    }

    
}