题解 | #【模板】队列#

public static void main(String[] args) {
	// TODO Auto-generated method stub
	 Scanner scan = new Scanner(System.in) ;
        int n = Integer.parseInt(scan.nextLine()) ;
        Main main = new Main();
        Quene1 q = new Quene1(n) ;
        while(scan.hasNextLine()) {
            String str = scan.nextLine() ;
            String arr[] = str.split(" ") ;
            if(arr[0].equals("push")) {
                q.push(Integer.parseInt(arr[1])) ;
            } else if(arr[0].equals("pop")) {
                q.pop() ;
            } else {
                q.top() ;
            }
	
	
      }		
}

}

int[] arr ;
int maxSize ;
int front;//头部
int rear;//尾部
public Quene1(int maxSize) {
    this.maxSize = maxSize ;
    arr = new int[maxSize] ;
    front = -1;
    rear = -1;
}
//加数据
public void push(int val) {
    if(rear==maxSize-1) {
        System.out.println("error") ;
    } else {
       rear++;
       arr[rear] = val;
    }
}
//取头部数据
public void top() {
    if(rear==front) {
        System.out.println("error") ;
    } else {
        System.out.println(arr[front+1]);
    }
}
//取数据
public void pop() {
    if(rear==front) {
        System.out.println("error") ;
    } else {
        front++;           
        System.out.println(arr[front]);
    }
}
//

}