[Java] Queue

먼저 집어 넣은 데이터가 먼저 나오는 FIFO (First In First Out)구조

N(2<= N <=100)개의 수를 Queue에 넣은 후 하나씩 꺼내 화면에 출력

import java.util.Scanner;
 
class Solution {
 
    static final int MAX_N = 100;
 
    static int front;
    static int rear;
    static int queue[] = new int[MAX_N];
 
    static void queueInit()
    {
        front = 0;
        rear = 0;
    }
 
    static boolean queueIsEmpty()
    {
        return (front == rear);
    }
 
    static boolean queueIsFull()
    {
        if ((front + 1) % MAX_N == rear)
        {
            return true;
        }
        else
        {
            return false;
        }
    }
 
    static boolean queueEnqueue(int value)
    {
        if (queueIsFull())
        {
            System.out.print("queue is full!");
            return false;
        }
        queue[front] = value;
        front++;
        if (front >= MAX_N)
        {
            front = MAX_N;
        }
 
        return true;
    }
 
    static Integer queueDequeue()
    {
        if (queueIsEmpty())
        {
            System.out.print("queue is empty!");
            return null;
        }
         
        Integer value = new Integer(queue[rear]);
 
        rear++;
        if (rear >= MAX_N)
        {
            rear = MAX_N;
        }
        return value;
    }
 
    public static void main(String arg[]) throws Exception {
        Scanner sc = new Scanner(System.in);
         
        int T = sc.nextInt();
 
        for (int test_case = 1; test_case <= T; test_case++)
        {
            int N = sc.nextInt();
 
            queueInit();
            for (int i = 0; i < N; i++)
            {
                int value = sc.nextInt();
                queueEnqueue(value);
            }
 
            System.out.print("#" + test_case + " ");
             
            while (!queueIsEmpty())
            {
                Integer value = queueDequeue();
                if (value != null)
                {
                    System.out.print(value.intValue() + " ");
                }
            }
            System.out.println();
        }
        sc.close();
    }
}