Im having an issue with the simulateOPT() methodthis is the p.pdf

I'm having an issue with the simulateOPT() method
this is the purpose:
this is my code:
import java.util.Scanner;
public class Main {
private static int n;
private static int[] referenceString;
private static int[] physicalFrames;
private static int[] victimPages;
private static int pageFaults;
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
int choice;
do {
System.out.println("0 - Exit");
System.out.println("1 - Input N");
System.out.println("2 - Input the reference string");
System.out.println("3 - Simulate the OPT algorithm");
System.out.println("4 - Simulate the NEW algorithm");
System.out.print("Select option: ");
choice = input.nextInt();
switch (choice) {
case 0:
System.out.println("Exiting the program...");
break;
case 1:

System.out.print("Enter the value of N (2-8): ");
n = input.nextInt();
if (n < 2 || n > 8) {
System.out.println("Invalid value of N!");
n = 0;
} else {
physicalFrames = new int[n];
victimPages = new int[n];
System.out.println("N set to " + n + ".");
}
break;
case 2:
if (n == 0) {
System.out.println("Please enter the value of N first!");
} else {
System.out.print("Enter the reference string (length at least " + n + ", max length 20): ");
String[] strArr = input.next().split("");
int len = strArr.length;
if (len < n || len > 20) {
System.out.println("Invalid length of reference string!");
} else {
referenceString = new int[len];
for (int i = 0; i < len; i++) {
int page = Integer.parseInt(strArr[i]);
if (page < 0 || page > 9) {
System.out.println("Invalid page number!");
referenceString = null;
break;
}
referenceString[i] = page;
}
if (referenceString != null) {
System.out.println("Reference string set to " + String.join("", strArr) + ".");
}
}
}

break;
case 3:
if (n == 0) {
} else if (referenceString == null) {
System.out.println("Please enter the reference string first!");
} else {
System.out.println("Simulating the OPT algorithm...");
simulateOPT();
}
break;
case 4:
if (n == 0) {
} else if (referenceString == null) {
System.out.println("Please enter the reference string first!");
} else {
System.out.println("Simulating the NEW algorithm...");
simulateNEW();
}
break;
default:
System.out.println("Invalid choice!");
break;
}
System.out.println();
} while (choice != 0);
}
private static void simulateOPT() {
pageFaults = 0;
int len = referenceString.length;
System.out.println("Reference StringtPhysical FramestPage FaultstVictim Pages");

for (int i = 0; i < len; i++) {
int page = referenceString[i];
boolean found = false;
for (int j = 0; j < n; j++) {
if (physicalFrames[j] == page) {
found = true;
break;
}
}
if (!found) {
pageFaults++;
int maxDist = 0;
int victimPage = -1;
for (int j = 0; j < n; j++) {
int dist = 0;
for (int k = i + 1; k < len; k++) {
dist++;
if (physicalFrames[j] == referenceString[k]) {
break;
}
}
if (dist > maxDist) {
maxDist = dist;
victimPage = j;
}
}
physicalFrames[victimPage] = page;
victimPages[i] = physicalFrames[victimPage];
}
else {
victimPages[i] = -1;
}
System.out.print(page + "ttt");
for (int j = 0; j < n; j++) {
if (physicalFrames[j] == -1) {
System.out.print("- ");

}
else {
System.out.print(physicalFrames[j] + " ");
}
}
System.out.print("tt" + pageFaults + "tt");
for (int j = 0; j < len; j++) {
if (victimPages[j] == -1) {
System.out.print("- ");
}
else {
System.out.print(victimPages[j] + " ");
}
}
}
System.out.println("nTotal Page Faults: " + pageFaults);
}
private static void simulateNEW() {
pageFaults = 0;
int len = referenceString.length;
int[] lastUsed = new int[10];
for (int i = 0; i < len; i++) {
int page = referenceString[i];
boolean found = false;
for (int j = 0; j < n; j++) {
if (physicalFrames[j] == page) {
found = true;
break;
}
}
if (!found) {
pageFaults++;
int victimIndex = -1;
for (int j = 0; j < n; j++) {

int p = physicalFrames[j];
if (lastUsed[p] == 0) {
victimIndex = j;
break;
}
if (lastUsed[p] < lastUsed[physicalFrames[victimIndex]]) {
victimIndex = j;
}
}
int victimPage = physicalFrames[victimIndex];
victimPages[i] = victimPage;
physicalFrames[victimIndex] = page;
lastUsed[page] = i + 1;
lastUsed[victimPage] = 0;
}
else {
victimPages[i] = -1;
}
System.out.print(page + "tt");
for (int j = 0; j < n; j++) {
System.out.print(physicalFrames[j] + "t");
}
System.out.print(pageFaults + "tt");
for (int j = 0; j < len; j++) {
if (victimPages[j] != 0) {
System.out.print(victimPages[j] + " ");
}
}
}
}
} 3-Simulate the OPT algorithm This option must first verify that a correct N and a correct
reference string were already provided by the user; otherwise an error message should be issued
and the program returns to the menu. If all the input data ( N and the reference string) is available
and correct, the simulation begins by printing the initial (empty) simulation table, for example:
Hint 1: Instead of the above reference string, the table will contain the ACTUAL reference string

that was entered by the user; of course, everyone can use their reference strings for testing the
correctness of the implementation. Using the reference strings from the readings to test your
code is a great idea. Hint 2: Instead of having 4 physical frames in the simulation table, we must
actually have N physical frames. So if the user has entered the value 6 for N using option 1 of the
menu, then the simulation table should look like this: Hint 3: Being a text only interface, clearly
we cannot display such a nice table, but rather an approximation of it; the table could instead
look like this or similar: The user must proceed with the STEP by STEP simulation of the OPT
algorithm by pressing a key after each step of the algorithm; just as in the examples from the
module 5 readings, each step of the simulation will fill a new column of the simulation table
(previous steps must also be visible) and the table is re-printed on the screen after each step. This
way, the user has an overview of all the previous steps and also of the current step. In the end,
the table will be completely filled with information, and the user will have the complete view of
the simulation. The total number of faults must also be displayed. In other words, the simulation
must follow very closely the examples of Demand Paging algorithms from Module 5 of this
course. Printing the explanations is optional.

Im having an issue with the simulateOPT() methodthis is the p.pdf

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Im having an issue with the simulateOPT() methodthis is the p.pdf