import java.util.ArrayList;

import java.util.Random;

import java.util.Scanner;

public class UniqueRandomNumber {

public static boolean isDuplicate(ArrayList<Integer> numbers, int randomNumber){

for (int i = 0; i < numbers.size(); i++) {

if (numbers.get(i) == randomNumber) {

return true;

}

}

return false;

}

public static void main(String args[]) {

Random random = new Random();

int uniqueNumberCount = 0, randomNumber, limit;

ArrayList<Integer> pastNumber = new ArrayList<>();

Scanner in = new Scanner(System.in);

System.out.print("Enter a limit of random number: ");

limit = in.nextInt();

for (int i = 0; uniqueNumberCount < limit; i++) {

randomNumber = random.nextInt(limit) + 1;

if (!isDuplicate(pastNumber, randomNumber)) {

System.out.println(randomNumber);

pastNumber.add(uniqueNumberCount++, randomNumber);

}

}

}

}