Vampire Numbers 1

Description: The following programs finds out all the 4 digit Vampire numbers defined as follows:

What are Vampire numbers?

A vampire number has an even number of digits and is formed by multiplying a pair of numbers containing half the number of digits of the result. The digits are taken from the original number in any order. Pairs of trailing zeroes are not allowed.

Example include:
1260 = 21 * 60
1827 = 21 * 87
2187 = 27 * 81

Primary Inputs: None

Primary Output: all the 4 digit Vampire numbers.

Platform Used: JDK 1.5 with Dr. Java.

Java

package com.coddicted;

class Vampire {
    void findVampire() {
        int arr[] = new int[4];
        for (int i = 1001; i < 10000; i++) {
            arr = getDigitCombo(i);
            rotateCombo(arr, i, 1);
        }
    }

    boolean vampireStraightCombo(int[] arr, int num) {
        if (checkIfVampire(arr[0], arr[1], arr[2], arr[3], num)) {
            System.out.println(num + " = " + (arr[0] * 10 + arr[1]) + " * " + (arr[2] * 10 + arr[3]));
            return true;
        } else if (checkIfVampire(arr[0], arr[2], arr[1], arr[3], num)) {
            System.out.println(num + " = " + (arr[0] * 10 + arr[2]) + " * " + (arr[1] * 10 + arr[3]));
            return true;
        } else if (checkIfVampire(arr[0], arr[3], arr[1], arr[2], num)) {
            System.out.println(num + " = " + (arr[0] * 10 + arr[3]) + " * " + (arr[1] * 10 + arr[2]));
            return true;
        }
        return false;
    }

    boolean vampireReverseCombo(int[] arr, int num) {
        if (checkIfVampire(arr[3], arr[2], arr[1], arr[0], num)) {
            System.out.println(num + " = " + (arr[3] * 10 + arr[2]) + " * " + (arr[1] * 10 + arr[0]));
            return true;
        } else if (checkIfVampire(arr[3], arr[1], arr[2], arr[0], num)) {
            System.out.println(num + " = " + (arr[3] * 10 + arr[1]) + " * " + (arr[2] * 10 + arr[0]));
            return true;
        } else if (checkIfVampire(arr[3], arr[0], arr[2], arr[1], num)) {
            System.out.println(num + " = " + (arr[3] * 10 + arr[0]) + " * " + (arr[2] * 10 + arr[1]));
            return true;
        }
        return false;
    }

    boolean checkIfVampire(int a, int b, int c, int d, int num) {
        int num1 = a * 10 + b;
        int num2 = c * 10 + d;
        if ((num1 * num2) == num) return true;
        return false;
    }

    void rotateCombo(int[] arr, int num, int count) {
        if (count == 5) return;
        if (vampireStraightCombo(arr, num)) return;
        else if (vampireReverseCombo(arr, num)) return;
        else {
            arr = rotateArray(arr);
            rotateCombo(arr, num, count + 1);
        }
    }

    int[] rotateArray(int[] arr) {
        int[] temp = new int[4];
        for (int i = 1; i < 4; i++) temp[i] = arr[i - 1];
        temp[0] = arr[3];
        return temp;
    }

    int[] getDigitCombo(int num) {
        int[] arr = new int[4];
        for (int i = 3; i >= 0; i--) {
            arr[i] = num % 10;
            num = (num - num % 10) / 10;
        }
        return arr;
    }

    public static void main(String[] args) {
        System.out.println("The vampire numbers are: ");
        Vampire v = new Vampire();
        v.findVampire();
    }
}

package com.coddicted;

class Vampire {

void findVampire() {

int arr[] = new int[4];

for (int i = 1001; i < 10000; i++) {

arr = getDigitCombo(i);

rotateCombo(arr, i, 1);

}

boolean vampireStraightCombo(int[] arr, int num) {

if (checkIfVampire(arr[0], arr[1], arr[2], arr[3], num)) {

System.out.println(num + " = " + (arr[0] * 10 + arr[1]) + " * " + (arr[2] * 10 + arr[3]));

return true;

} else if (checkIfVampire(arr[0], arr[2], arr[1], arr[3], num)) {

System.out.println(num + " = " + (arr[0] * 10 + arr[2]) + " * " + (arr[1] * 10 + arr[3]));

return true;

} else if (checkIfVampire(arr[0], arr[3], arr[1], arr[2], num)) {

System.out.println(num + " = " + (arr[0] * 10 + arr[3]) + " * " + (arr[1] * 10 + arr[2]));

return true;

}

return false;

}

boolean vampireReverseCombo(int[] arr, int num) {

if (checkIfVampire(arr[3], arr[2], arr[1], arr[0], num)) {

System.out.println(num + " = " + (arr[3] * 10 + arr[2]) + " * " + (arr[1] * 10 + arr[0]));

return true;

} else if (checkIfVampire(arr[3], arr[1], arr[2], arr[0], num)) {

System.out.println(num + " = " + (arr[3] * 10 + arr[1]) + " * " + (arr[2] * 10 + arr[0]));

return true;

} else if (checkIfVampire(arr[3], arr[0], arr[2], arr[1], num)) {

System.out.println(num + " = " + (arr[3] * 10 + arr[0]) + " * " + (arr[2] * 10 + arr[1]));

return true;

}

return false;

}

boolean checkIfVampire(int a, int b, int c, int d, int num) {

int num1 = a * 10 + b;

int num2 = c * 10 + d;

if ((num1 * num2) == num) return true;

return false;

}

void rotateCombo(int[] arr, int num, int count) {

if (count == 5) return;

if (vampireStraightCombo(arr, num)) return;

else if (vampireReverseCombo(arr, num)) return;

else {

arr = rotateArray(arr);

rotateCombo(arr, num, count + 1);

}

int[] rotateArray(int[] arr) {

int[] temp = new int[4];

for (int i = 1; i < 4; i++) temp[i] = arr[i - 1];

temp[0] = arr[3];

return temp;

}

int[] getDigitCombo(int num) {

int[] arr = new int[4];

for (int i = 3; i >= 0; i--) {

arr[i] = num % 10;

num = (num - num % 10) / 10;

}

return arr;

}

public static void main(String[] args) {

System.out.println("The vampire numbers are: ");

Vampire v = new Vampire();

v.findVampire();

}

4/5 - (5 votes)

One comment on “Vampire Numbers”

Reply Sam Biba Oct 1,2019 4:12 pm

import java.util.*;
class Vam_Find//    E.g.->1260,1395,126000,...
{
    public static boolean isVam(int n)
    {  
        String no=n+"";
        char arr[]=new char[no.length()];
        String s1="",s2="";
        for(int i=0;i<no.length();i++)
        {
            char ch=no.charAt(i);
            arr[i]=ch;
        }
        char arr_[]=new char[arr.length];
        Arrays.sort(arr);        
        if(no.length()%2==0)
        {
            for(int i=1;i<n;i++)
            {
                if(n%i==0)
                {
                    s1=i+"";
                    s2=(n/i)+"";
                    if(s1.length()==s2.length())
                    {
                        String t_="";
                        for(int j=0;j<(s1+s2).length();j++)
                        {
                            char ch=(s1+s2).charAt(j);
                            arr_[j]=ch;
                        }                                       
                        Arrays.sort(arr_);
                        if(Arrays.equals(arr,arr_))
                        break;                     
                    }
                }
            }
        }
        if(Arrays.equals(arr,arr_))        
        return true;
        else
        return false;
    }
    public static void main(String args[])
    {
        Scanner sc=new Scanner(System.in);
        System.out.print("\nEnter a range of numbers: ");
        int s=sc.nextInt();
        int e=sc.nextInt();
        System.out.println("\nThe Vampire number/s from "+s+" to "+e+" is/are: ");
        for(int i=s;i<=e;i++)
        {
            if(isVam(i))
            System.out.print(i+"\t");
        }
    }
}

import java.util.*;

class Vam_Find// E.g.->1260,1395,126000,...

{

public static boolean isVam(int n)

{

String no=n+"";

char arr[]=new char[no.length()];

String s1="",s2="";

for(int i=0;i<no.length();i++)

{

char ch=no.charAt(i);

arr[i]=ch;

}

char arr_[]=new char[arr.length];

Arrays.sort(arr);

if(no.length()%2==0)

{

for(int i=1;i<n;i++)

{

if(n%i==0)

{

s1=i+"";

s2=(n/i)+"";

if(s1.length()==s2.length())

{

String t_="";

for(int j=0;j<(s1+s2).length();j++)

{

char ch=(s1+s2).charAt(j);

arr_[j]=ch;

}

Arrays.sort(arr_);

if(Arrays.equals(arr,arr_))

break;

}

if(Arrays.equals(arr,arr_))

return true;

else

return false;

}

public static void main(String args[])

{

Scanner sc=new Scanner(System.in);

System.out.print("\nEnter a range of numbers: ");

int s=sc.nextInt();

int e=sc.nextInt();

System.out.println("\nThe Vampire number/s from "+s+" to "+e+" is/are: ");

for(int i=s;i<=e;i++)

{

if(isVam(i))

System.out.print(i+"\t");

}

Coddicted

Vampire Numbers 1

Table of Contents

What are Vampire numbers?

Java

One comment on “Vampire Numbers”

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