页面置换算法OPTjava实现

以下是页面置换算法OPT的Java实现：

import java.util.*;

public class Opt {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("请输入物理块数量：");
        int frameNum = sc.nextInt();
        System.out.print("请输入访问页面总数：");
        int pageNum = sc.nextInt();
        int[] pages = new int[pageNum];
        System.out.print("请输入要访问的页面号（以空格分隔）：");
        for (int i = 0; i < pageNum; i++) {
            pages[i] = sc.nextInt();
        }
        sc.close();

        int[] frames = new int[frameNum];
        int[] nextUse = new int[frameNum];
        Arrays.fill(frames, -1);
        Arrays.fill(nextUse, pageNum);

        int pageFault = 0;
        for (int i = 0; i < pageNum; i++) {
            int page = pages[i];
            boolean hit = false;
            for (int j = 0; j < frameNum; j++) {
                if (frames[j] == page) {
                    hit = true;
                    break;
                }
            }
            if (!hit) {
                pageFault++;
                int victim = 0;
                for (int j = 1; j < frameNum; j++) {
                    if (nextUse[j] > nextUse[victim]) {
                        victim = j;
                    }
                }
                frames[victim] = page;
            }
            for (int j = 0; j < frameNum; j++) {
                if (frames[j] != -1) {
                    nextUse[j] = Integer.MAX_VALUE;
                    for (int k = i + 1; k < pageNum; k++) {
                        if (pages[k] == frames[j]) {
                            nextUse[j] = k;
                            break;
                        }
                    }
                }
            }
        }

        double pageFaultRate = (double) pageFault / pageNum;
        System.out.println("缺页次数：" + pageFault);
        System.out.println("缺页率：" + pageFaultRate);
    }
}