LRU REPLACEMENT ALGORITHM

import java.util.Arrays;
import java.util.Scanner;

public class LeastRecentlyUsedAlgorithm {

    public static void main(String[] args) {
        // TODO Auto-generated method stub

        Scanner sc = new Scanner(System.in);
        int k = 0;
        System.out.println("enter no. of frames: ");
        int f = sc.nextInt();
        int frame1[] = new int[f];
        int a[] = new int[f];
        int b[] = new int[f];
        for (int i = 0; i < f; i++) {
            frame1[i] = -1;
            a[i] = -1;
            b[i] = -1;
        }
        System.out.println("enter the no of pages ");
        int n = sc.nextInt();
        int[] pages = new int[n];
        System.out.println("enter the page no ");
        for (int j = 0; j < n; j++)
            pages[j] = sc.nextInt();
        int pgf = 0;
        int chn = 0;

        int pg = 0;
        System.out.println("Accessed Page\tframes");
        for (pg = 0; pg < n; pg++) {
            int page = pages[pg];
            boolean flag = true;

            for (int j = 0; j < f; j++) {
                if (page == frame1[j]) {
                    flag = false;
                    break;
                }
            }

            for (int j = 0; j < f && flag; j++) {
                if (frame1[j] == a[f - 1]) {
                    k = j;
                    break;
                }
            }

            if (flag) {
                frame1[k] = page;

                System.out.println("\t" + page + "\t" + Arrays.toString(frame1)
                        + "   Fault");
                pgf++;

            } else {

                System.out
                        .println("\t" + page + "\t" + Arrays.toString(frame1));

            }
            int p = 1;
            b[0] = page;
            for (int j = 0; j < a.length; j++) {
                if (page != a[j] && p < f) {
                    b[p] = a[j];
                    p++;
                }
            }
            for (int j = 0; j < f; j++) {
                a[j] = b[j];
            }

        }

        System.out.println("Page fault:" + pgf);
    }

}

/*enter no. of frames:
3
enter the no of pages
20
enter the page no
7 0 1 2 0 3 0 4 2 3 0 3 2 1 2 0 1 7 0 1
Accessed Page   frames
    7   [7, -1, -1]   Fault
    0   [7, 0, -1]   Fault
    1   [7, 0, 1]   Fault
    2   [2, 0, 1]   Fault
    0   [2, 0, 1]
    3   [2, 0, 3]   Fault
    0   [2, 0, 3]
    4   [4, 0, 3]   Fault
    2   [4, 0, 2]   Fault
    3   [4, 3, 2]   Fault
    0   [0, 3, 2]   Fault
    3   [0, 3, 2]
    2   [0, 3, 2]
    1   [1, 3, 2]   Fault
    2   [1, 3, 2]
    0   [1, 0, 2]   Fault
    1   [1, 0, 2]
    7   [1, 0, 7]   Fault
    0   [1, 0, 7]
    1   [1, 0, 7]

*/