problem

实验内容：
　　编写一个磁盘调度程序，模拟操作系统对磁盘的调度。

实验目的：
本实验要求学生独立设计并实现磁盘调度模拟程序，以加深对磁盘调度特点和各种磁盘调度算法的理解。

实验要求：
　　可以随机输入磁道请求序列，当前磁头位置和磁头移动方向，支持先来先服务、最短寻道时间优先、扫描、循环扫描调度算法，能够输出磁头移动经过的磁道序列。具体信息见测试用例格式说明。

测试用例格式如下：
输入：

磁盘调度算法

当前磁头位置

磁头移动方向

磁道请求序列（磁道1,磁道2,磁道3,...)

其中：

(1) 调度算法选项为：

               1----先来先服务

               2----最短寻道时间优先

               3----扫描法(SCAN)

               4----循环扫描法(C-SCAN)

(2) 磁头移动方向选项为：

1----向磁头号增大方向移动

0----向磁头号减小方向移动

输出：

磁头移动经过的磁道序列（磁道1，磁道2，磁道3）

磁头移动经过的总磁道数

测试用例

测试输入	期待的输出
1 53 1 98,183,37,122,14,124,65,67	53,98,183,37,122,14,124,65,67 640

ac code

import java.util.*;



public class Main {

    private static int method;
    private static int way;
    private static int now;
    private static int count = 0;
    private static int len;
    private static Integer[] inps;

    public static void main(String[] args) {
    // write your code here
        Scanner scanner = new Scanner(System.in);
        method = scanner.nextInt();
        now = scanner.nextInt();
        way = scanner.nextInt();
        scanner.nextLine();
        String str = scanner.nextLine();
        len = str.split(",").length;
        inps = new Integer[len];
        for (int i = 0;i < len; i++){
            inps[i] = new Integer(str.split(",")[i]);
        }
        handle();
    }

    private static void handle() {
        switch (method) {
            case 1:
                fcfs();
                break;
            case 2:
                stf();
                break;
            case 3:
                scan();
                break;
            case 4:
                cscan();
                break;
        }
    }

    private static void fcfs() {
        System.out.print(now);
        for (int i : inps) {
            count += Math.abs(i - now);
            now = i;
            System.out.print("," + now);
        }
        System.out.println();
        System.out.println(count);
    }

    private static void stf() {
        System.out.print(now);
        List<Integer> pages = getList();
        for (int i = 0 ;i < len;i++) {
            int max = Math.abs(pages.get(0) - now);
            int idx = 0;
            for(Integer ech : pages){
                if (Math.abs(ech - now) < max) {
                    max = Math.abs(ech - now);
                    idx = pages.indexOf(ech);
                }
            }
            System.out.print("," + pages.get(idx));
            count += Math.abs(now - pages.get(idx));
            now = pages.get(idx);
            pages.remove(idx);
        }
        System.out.println();
        System.out.println(count);

    }

    private static void scan() {
        System.out.print(now);
        Arrays.sort(inps);
        List<Integer> pages = getList();
        if (way == 1) {
            int idx = 0;
            for (Integer ech : pages) {
                if (ech > now) {
                    idx = pages.indexOf(ech);
                    break;
                }
            }
            for (int i = idx; i < len; i++) {
                int ech = pages.get(i);
                count += Math.abs(ech - now);
                now = ech;
                System.out.print("," + now);
            }
            if (idx != 0) {
                for (int i = idx - 1; i >= 0; i--) {
                    int ech = pages.get(i);
                    count += Math.abs(ech - now);
                    now = ech;
                    System.out.print("," + now);
                }
            }
        }else {
            int idx = 0;
            for (Integer ech : pages) {
                if (now > ech) {
                    idx = pages.indexOf(ech);
                }else {
                    break;
                }
            }
            for (int i = idx; i >= 0; i--) {
                int ech = pages.get(i);
                count += Math.abs(ech - now);
                now = ech;
                System.out.print("," + now);
            }
            if (idx != 0) {
                for (int i = idx + 1; i < len; i++) {
                    int ech = pages.get(i);
                    count += Math.abs(ech - now);
                    now = ech;
                    System.out.print("," + now);
                }
            }
        }
        System.out.println();
        System.out.println(count);
    }
    private static void cscan() {
        System.out.print(now);
        Arrays.sort(inps);
        List<Integer> pages = getList();
        if (way == 1) {
            int idx = 0;
            for (Integer ech : pages) {
                if (ech > now) {
                    idx = pages.indexOf(ech);
                    break;
                }
            }
            for (int i = idx; i < len; i++) {
                int ech = pages.get(i);
                count += Math.abs(ech - now);
                now = ech;
                System.out.print("," + now);
            }
            if (idx != 0) {
                for (int i = 0; i < idx; i++) {
                    int ech = pages.get(i);
                    count += Math.abs(ech - now);
                    now = ech;
                    System.out.print("," + now);
                }
            }
        }else {
            int idx = 0;
            for (Integer ech : pages) {
                if (now > ech) {
                    idx = pages.indexOf(ech);
                }else {
                    break;
                }
            }
            for (int i = idx; i >= 0; i--) {
                int ech = pages.get(i);
                count += Math.abs(ech - now);
                now = ech;
                System.out.print("," + now);
            }
            if (idx != 0) {
                for (int i = len - 1; i > idx; i--) {
                    int ech = pages.get(i);
                    count += Math.abs(ech - now);
                    now = ech;
                    System.out.print("," + now);
                }
            }
        }
        System.out.println();
        System.out.println(count);
    }

    private static LinkedList<Integer> getList(){
        return new LinkedList<>(Arrays.asList(inps));
    }


}