将FCFS算法，SJF算法，RR算法，PSA算法用一个java程序写出来

以下是一个使用Java语言实现四种调度算法的示例代码：

1. FCFS算法

import java.util.*;

public class FCFS {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入作业数：");
        int n = scanner.nextInt();

        int[] arriveTime = new int[n]; // 到达时间
        int[] serviceTime = new int[n]; // 服务时间

        for (int i = 0; i < n; i++) {
            System.out.print("请输入第" + (i+1) + "个作业的到达时间和服务时间：");
            arriveTime[i] = scanner.nextInt();
            serviceTime[i] = scanner.nextInt();
        }

        int[] finishTime = new int[n]; // 完成时间
        int[] waitingTime = new int[n]; // 等待时间
        int[] turnAroundTime = new int[n]; // 周转时间

        finishTime[0] = serviceTime[0];
        turnAroundTime[0] = finishTime[0] - arriveTime[0];
        waitingTime[0] = turnAroundTime[0] - serviceTime[0];

        for (int i = 1; i < n; i++) {
            finishTime[i] = finishTime[i-1] + serviceTime[i];
            turnAroundTime[i] = finishTime[i] - arriveTime[i];
            waitingTime[i] = turnAroundTime[i] - serviceTime[i];
        }

        double avgWaitingTime = 0.0;
        double avgTurnAroundTime = 0.0;

        for (int i = 0; i < n; i++) {
            avgWaitingTime += waitingTime[i];
            avgTurnAroundTime += turnAroundTime[i];
        }

        avgWaitingTime /= n;
        avgTurnAroundTime /= n;

        System.out.println("作业\t到达时间\t服务时间\t完成时间\t等待时间\t周转时间");
        for (int i = 0; i < n; i++) {
            System.out.println((i+1) + "\t" + arriveTime[i] + "\t\t" + serviceTime[i] + "\t\t" + finishTime[i] + "\t\t" + waitingTime[i] + "\t\t" + turnAroundTime[i]);
        }
        System.out.println("平均等待时间：" + avgWaitingTime);
        System.out.println("平均周转时间：" + avgTurnAroundTime);
    }
}

2. SJF算法

import java.util.*;

public class SJF {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入作业数：");
        int n = scanner.nextInt();

        int[] arriveTime = new int[n]; // 到达时间
        int[] serviceTime = new int[n]; // 服务时间

        for (int i = 0; i < n; i++) {
            System.out.print("请输入第" + (i+1) + "个作业的到达时间和服务时间：");
            arriveTime[i] = scanner.nextInt();
            serviceTime[i] = scanner.nextInt();
        }

        int[] finishTime = new int[n]; // 完成时间
        int[] waitingTime = new int[n]; // 等待时间
        int[] turnAroundTime = new int[n]; // 周转时间
        boolean[] visited = new boolean[n]; // 标记作业是否已经完成

        int currentTime = 0;
        int count = 0;

        while (count < n) {
            int minServiceTime = Integer.MAX_VALUE;
            int minIndex = -1;
            for (int i = 0; i < n; i++) {
                if (!visited[i] && arriveTime[i] <= currentTime && serviceTime[i] < minServiceTime) {
                    minServiceTime = serviceTime[i];
                    minIndex = i;
                }
            }
            if (minIndex != -1) {
                finishTime[minIndex] = currentTime + serviceTime[minIndex];
                turnAroundTime[minIndex] = finishTime[minIndex] - arriveTime[minIndex];
                waitingTime[minIndex] = turnAroundTime[minIndex] - serviceTime[minIndex];
                visited[minIndex] = true;
                count++;
                currentTime = finishTime[minIndex];
            } else {
                currentTime++;
            }
        }

        double avgWaitingTime = 0.0;
        double avgTurnAroundTime = 0.0;

        for (int i = 0; i < n; i++) {
            avgWaitingTime += waitingTime[i];
            avgTurnAroundTime += turnAroundTime[i];
        }

        avgWaitingTime /= n;
        avgTurnAroundTime /= n;

        System.out.println("作业\t到达时间\t服务时间\t完成时间\t等待时间\t周转时间");
        for (int i = 0; i < n; i++) {
            System.out.println((i+1) + "\t" + arriveTime[i] + "\t\t" + serviceTime[i] + "\t\t" + finishTime[i] + "\t\t" + waitingTime[i] + "\t\t" + turnAroundTime[i]);
        }
        System.out.println("平均等待时间：" + avgWaitingTime);
        System.out.println("平均周转时间：" + avgTurnAroundTime);
    }
}

3. RR算法

import java.util.*;

public class RR {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入作业数：");
        int n = scanner.nextInt();

        int[] arriveTime = new int[n]; // 到达时间
        int[] serviceTime = new int[n]; // 服务时间

        for (int i = 0; i < n; i++) {
            System.out.print("请输入第" + (i+1) + "个作业的到达时间和服务时间：");
            arriveTime[i] = scanner.nextInt();
            serviceTime[i] = scanner.nextInt();
        }

        int quantum = 2; // 时间片大小

        int[] finishTime = new int[n]; // 完成时间
        int[] waitingTime = new int[n]; // 等待时间
        int[] turnAroundTime = new int[n]; // 周转时间

        int[] remainTime = new int[n]; // 剩余服务时间
        for (int i = 0; i < n; i++) {
            remainTime[i] = serviceTime[i];
        }

        int currentTime = 0;
        int count = 0;

        while (count < n) {
            boolean flag = false;
            for (int i = 0; i < n; i++) {
                if (arriveTime[i] <= currentTime && remainTime[i] > 0) {
                    if (remainTime[i] > quantum) {
                        currentTime += quantum;
                        remainTime[i] -= quantum;
                    } else {
                        currentTime += remainTime[i];
                        finishTime[i] = currentTime;
                        turnAroundTime[i] = finishTime[i] - arriveTime[i];
                        waitingTime[i] = turnAroundTime[i] - serviceTime[i];
                        remainTime[i] = 0;
                        count++;
                    }
                    flag = true;
                }
            }
            if (!flag) {
                currentTime++;
            }
        }

        double avgWaitingTime = 0.0;
        double avgTurnAroundTime = 0.0;

        for (int i = 0; i < n; i++) {
            avgWaitingTime += waitingTime[i];
            avgTurnAroundTime += turnAroundTime[i];
        }

        avgWaitingTime /= n;
        avgTurnAroundTime /= n;

        System.out.println("作业\t到达时间\t服务时间\t完成时间\t等待时间\t周转时间");
        for (int i = 0; i < n; i++) {
            System.out.println((i+1) + "\t" + arriveTime[i] + "\t\t" + serviceTime[i] + "\t\t" + finishTime[i] + "\t\t" + waitingTime[i] + "\t\t" + turnAroundTime[i]);
        }
        System.out.println("平均等待时间：" + avgWaitingTime);
        System.out.println("平均周转时间：" + avgTurnAroundTime);
    }
}

4. PSA算法

import java.util.*;

public class PSA {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入作业数：");
        int n = scanner.nextInt();

        int[] arriveTime = new int[n]; // 到达时间
        int[] serviceTime = new int[n]; // 服务时间
        int[] priority = new int[n]; // 优先级

        for (int i = 0; i < n; i++) {
            System.out.print("请输入第" + (i+1) + "个作业的到达时间、服务时间和优先级：");
            arriveTime[i] = scanner.nextInt();
            serviceTime[i] = scanner.nextInt();
            priority[i] = scanner.nextInt();
        }

        int[] finishTime = new int[n]; // 完成时间
        int[] waitingTime = new int[n]; // 等待时间
        int[] turnAroundTime = new int[n]; // 周转时间
        boolean[] visited = new boolean[n]; // 标记作业是否已经完成

        int currentTime = 0;
        int count = 0;

        while (count < n) {
            int maxPriority = Integer.MIN_VALUE;
            int maxIndex = -1;
            for (int i = 0; i < n; i++) {
                if (!visited[i] && arriveTime[i] <= currentTime && priority[i] > maxPriority) {
                    maxPriority = priority[i];
                    maxIndex = i;
                }
            }
            if (maxIndex != -1) {
                finishTime[maxIndex] = currentTime + serviceTime[maxIndex];
                turnAroundTime[maxIndex] = finishTime[maxIndex] - arriveTime[maxIndex];
                waitingTime[maxIndex] = turnAroundTime[maxIndex] - serviceTime[maxIndex];
                visited[maxIndex] = true;
                count++;
                currentTime = finishTime[maxIndex];
            } else {
                currentTime++;
            }
        }

        double avgWaitingTime = 0.0;
        double avgTurnAroundTime = 0.0;

        for (int i = 0; i < n; i++) {
            avgWaitingTime += waitingTime[i];
            avgTurnAroundTime += turnAroundTime[i];
        }

        avgWaitingTime /= n;
        avgTurnAroundTime /= n;

        System.out.println("作业\t到达时间\t服务时间\t优先级\t完成时间\t等待时间\t周转时间");
        for (int i = 0; i < n; i++) {
            System.out.println((i+1) + "\t" + arriveTime[i] + "\t\t" + serviceTime[i] + "\t\t" + priority[i] + "\t\t" + finishTime[i] + "\t\t" + waitingTime[i] + "\t\t" + turnAroundTime[i]);
        }
        System.out.println("平均等待时间：" + avgWaitingTime);
        System.out.println("平均周转时间：" + avgTurnAroundTime);
    }
}