Problem Description

Write a Java program to check if a number is a Fascinating number. When a number(3 digits or more) is multiplied by 2 and 3, and when both these products are concatenated with the original number, then it results in all digits from 1 to 9 present exactly once.

Code

FascinatingNumber.java

public class FascinatingNumber {
    public static void main(String[] args) {
        int num = 192;
        int num2 = num * 2;
        int num3 = num * 3;

        String str = "" + num + num2 + num3;
        boolean flag = true;

        for (char c = '1'; c <= '9'; c++) {
            int count = 0;
            for (int i = 0; i < str.length(); i++) {
                char ch = str.charAt(i);
                if (ch == c)
                    count++;
            }
            if (count != 1) {
                flag = false;
                break;
            }
        }

        if (flag)
            System.out.println(num + " is a Fascinating Number.");
        else
            System.out.println(num + " is not a Fascinating Number.");
    }
}

Output

192 is a Fascinating Number.

Explanation

Concatenate: num + num*2 + num*3.
Verify: Check if the result contains all digits from 1 to 9 exactly once.

Java Program to Check Fascinating Number

Problem Description

Code

Output

Explanation

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