Java實作SJF演算法調度,要求測試資料可以隨即輸入或從檔案中讀入;
必須考慮到作業的到達時間;
最終能夠計算每一個作業的周轉時間、帶權週轉時間,並為程式碼加上中文註解
import java.util.ArrayList; import java.util.Comparator; import java.util.List; import java.util.Random; public class test { static class Job { public int jobId; public int arriveTime; public int needTime; public int finishTime; public int turnover; public double weightTurnover; public Job(int jobId, int arriveTime, int needTime) { this.jobId = jobId; this.arriveTime = arriveTime; this.needTime = needTime; } } public static void main(String[] args) { List<Job> jobList = new ArrayList<>(); Random random = new Random(); int jobSize = 5; int rangeArriveTime = 5; int rangeNeedTime = 10; for (int i = 0; i < jobSize; i++) { Job job = new Job(i, random.nextInt(rangeArriveTime), random.nextInt(rangeNeedTime) + 1); jobList.add(job); } jobList.sort(Comparator.comparingInt(o -> o.arriveTime)); int currentTime = 0; int totalTurnover = 0; double totalWeightTurnover = 0; int completeJobNum = 0; while (completeJobNum < jobList.size()) { int shortestNeedTime = Integer.MAX_VALUE; Job shortestNeedJob = null; for (Job job : jobList) { if (job.finishTime > 0) { continue; } if (job.arriveTime <= currentTime && job.needTime < shortestNeedTime) { shortestNeedTime = job.needTime; shortestNeedJob = job; } } currentTime += shortestNeedJob.needTime; shortestNeedJob.finishTime = currentTime; shortestNeedJob.turnover = shortestNeedJob.finishTime - shortestNeedJob.arriveTime; shortestNeedJob.weightTurnover = (double) shortestNeedJob.turnover / shortestNeedJob.needTime; totalTurnover += shortestNeedJob.turnover; totalWeightTurnover += shortestNeedJob.weightTurnover; completeJobNum++; } for (Job job : jobList) { System.out.println("作业" + job.jobId + "的周转时间为" + job.turnover + ",带权周转时间为" + job.weightTurnover); } System.out.println("平均周转时间为" + (double) totalTurnover / jobList.size()); System.out.println("带权平均周转时间为" + totalWeightTurnover / jobList.size()); } }
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