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));
}
}
