import java.util.Scanner;
import java.lang.Math;
public class Main
{
public static void main(String args[])
{
int sum = 0, n;
Scanner sc = new Scanner(System.in);
System.out.print("Enter the number to check: ");
n = sc.nextInt();
int square = n * n;
while(square != 0)
{
int digit = square % 10;
sum = sum + digit;
square = square / 10;
}
if(n == sum)
System.out.println(n + " is a Neon Number.");
else
System.out.println(n + " is not a Neon Number.");
}
}
import java.util.Scanner;
import java.lang.Math;
public class Main
{
public static int convertDecimalToBinary(int dec) {
int rem,b1=0;
int rev = 1;
while (dec > 0) {
rem = dec % 2;
dec = dec / 2;
b1 = b1 + rem * rev;
rev = rev * 10;
}
return b1;
}
public static void main(String args[])
{
Scanner in = new Scanner(System.in);
System.out.print("Enter a number : ");
int num = in.nextInt();
int decimal = convertDecimalToBinary(num);
System.out.println("Binary to Decimal");
System.out.println(num + " = " + decimal);
}
}
import java.util.Scanner;
import java.lang.Math;
public class Main
{
public static void main(String args[])
{
Scanner in = new Scanner(System.in);
System.out.print("Enter a number to check: ");
int num = in.nextInt();
int count=0;
int square = num*num;
int temp = num;
while(temp>0)
{
count++;
temp=temp/10;
}
int lastDigit = (int) (square%(Math.pow(10, count)));
if(num == lastDigit)
System.out.println(num+ " is an automorphic number.");
else
System.out.println(num+ " is not an automorphic number.");
}
}
import java.util.Scanner;
import java.lang.Math;
public class Main
{
static boolean isArmstrong(int n)
{
int temp, digits=0, last=0, sum=0;
temp=n;
while(temp>0)
{
temp = temp/10;
digits++;
}
temp = n;
while(temp>0)
{
last = temp % 10;
sum += (Math.pow(last, digits));
temp = temp/10;
}
if(n==sum)
return true;
else return false;
}
public static void main(String args[])
{
int num;
Scanner sc= new Scanner(System.in);
System.out.print("Enter the limit: ");
num=sc.nextInt();
if(isArmstrong(num))
System.out.print(num+ " is armstrong Number ");
}
}
import java.util.*;
public class Main
{
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println( " enter a value");
int n1=0,n2=1,n3,i,count;
count = sc.nextInt();
for(i=1;i<=count;++i)//loop starts from 2 because 0 and 1 are already printed
{
n3=n1+n2;
System.out.print(" "+n1);
n1=n2;
n2=n3;
}
}}
import java.util.*;
public class Main
{public static int isHappyNumber(int num){
int rem = 0, sum = 0;
while(num > 0){
rem = num%10;
sum = sum + (rem*rem);
num = num/10;
}
return sum;
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println( " enter a value");
int num = sc.nextInt();
int result = num;
while(result != 1 && result != 4){
result = isHappyNumber(result);
}
if(result == 1)
System.out.println(num + " is a happy number");
else if(result == 4)
System.out.println(num + " is not a happy number");
}
}
import java.util.Scanner;
public class Main
{
public static void main(String[] args) {
int n, remainder = 1, number, sum = 0;
Scanner sc = new Scanner(System.in);
System.out.print("Enter a number you want to check: ");
n = sc.nextInt();
number = n;
while (number > 9)
{
while (number > 0)
{
remainder = number % 10;
sum = sum + remainder;
number = number / 10;
}
number = sum;
sum = 0;
}
if (number == 1)
{
System.out.println("The given number is a magic number.");
}
else
{
System.out.println("The given number is not a magic number.");
}
}
}
import java.util.Scanner;
import java.util.Random;
public class Main
{
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter a word: ");
String word = scanner.nextLine();
scanner.close();
String convertedWord = convertWord(word);
System.out.println("Converted word: " + convertedWord);
}
private static String convertWord(String word)
{
StringBuilder converted = new StringBuilder();
for (int i = 0; i < word.length(); i++)
{char convertedChar;
char c = word.charAt(i);
if (c!=' '){
convertedChar = convertCharacter(c);}else{convertedChar =' ';}
converted.append(convertedChar);
}
return converted.toString();
}
private static char convertCharacter(char c)
{
if (isVowel(c))
{
return findNearestConsonant(c);
}
else
{
return findNearestVowel(c);
}
}
private static boolean isVowel(char c)
{
c = Character.toLowerCase(c);
return c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u';
}
private static char findNearestConsonant(char c)
{
while (true)
{
c--;
if (!isVowel(c))
{
return c;
}
}
}
private static char findNearestVowel(char c)
{
while (true)
{
c++;
if (isVowel(c))
{
return c;
}
}
}
}
import java.util.Scanner;
import java.util.Random;
public class Main
{
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter a string: ");
String inputString = scanner.nextLine();
String[] words = inputString.split(" ");
System.out.println("Words with repeating characters:");
for (String word : words)
{
if (hasRepeatingCharacters(word))
{
System.out.println(word);
}
}
scanner.close();
}
private static boolean hasRepeatingCharacters(String word)
{
for (int I = 0; I < word.length() - 1; I++)
{
char currentChar = word.charAt(I);
for (int j = I + 1; j < word.length(); j++)
{
if (currentChar == word.charAt(j))
{
return true;
}
}
}
return false;
}
}
Enter a string: bbn bnb vbn xcdxx
Words with repeating characters:
bbn
bnb
xcdxx
Write a program to form a square Matrix of characters and display the row and column having the max valued characters .
import java.util.Scanner;
import java.util.Random;
public class Main
{
public static void main(String[] args) {
int size = 5;
char[][] matrix = generateRandomMatrix(size);
System.out.println("Matrix:");
displayMatrix(matrix);
int[] maxIndices = findMaxValueIndices(matrix);
int maxRow = maxIndices[0];
int maxCol = maxIndices[1];
System.out.println("\nRow and column with maximum valued character:");
System.out.println("Row: " + maxRow);
System.out.println("Column: " + maxCol);
}
public static char[][] generateRandomMatrix(int size)
{
char[][] matrix = new char[size][size];
Random random = new Random();
for (int i = 0; i < size; i++)
{
for (int j = 0; j < size; j++)
{
matrix[i][j] = (char) (random.nextInt(26) + 'A');
}
}
return matrix;
}
public static void displayMatrix(char[][] matrix)
{
int size = matrix.length;
for (int i = 0; i < size; i++)
{
for (int j = 0; j < size; j++)
{
System.out.print(matrix[i][j] + " " );
}
System.out.println();
}
}
public static int[] findMaxValueIndices(char[][] matrix)
{
int size = matrix.length;
int maxRow = 0;
int maxCol = 0;
int maxValue = matrix[maxRow][maxCol];
for (int i = 0; i < size; i++)
{
for (int j = 0; j < size; j++)
{
if (matrix[i][j] > maxValue)
{
maxRow = i;
maxCol = j;
maxValue = matrix[i][j];
}
}
}
return new int[] { maxRow, maxCol };
}
}
Matrix:
L T B G E
R I K G Q
W R L O D
S X V O B
B Y U O G
Row and column with maximum valued character:
Row: 4
Column: 1
import java.util.Scanner;
public class Main
{
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter a number: ");
int number = scanner.nextInt();
scanner.close();
if (isFascinatingNumber(number))
{
System.out.println(number + " is a fascinating number.");
}
else
{
System.out.println(number + " is not a fascinating number.");
}
}
private static boolean isFascinatingNumber(int number)
{
String concatenatedNumber = String.valueOf(number) + String.valueOf(number * 2) + String.valueOf(number * 3);
int digitCount = countDigits(concatenatedNumber);
int[] frequency = new int[10];
for (int i = 0; i < digitCount; i++)
{
char digitChar = concatenatedNumber.charAt(i);
if (!Character.isDigit(digitChar) || frequency[digitChar - '0'] > 0)
{
return false;
}
frequency[digitChar - '0']++;
}
return true;
}
private static int countDigits(String number)
{
return number.length();
}
}
KaprekarNumbers
import java.util.Scanner;
public class Main
{
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter the value of p: ");
int p = scanner.nextInt();
System.out.print("Enter the value of q (where p < q): ");
int q = scanner.nextInt();
scanner.close();
if (p >= q)
{
System.out.println("Invalid input. Please make sure p < q.");
return;
}
int count = countKaprekarNumbers(p, q);
System.out.println("Number of Kaprekar numbers between " + p + " and " + q + ": " + count);
}
private static int countKaprekarNumbers(int p, int q)
{
int count = 0;
for (int num = p; num <= q; num++)
{
if (isKaprekarNumber(num))
{
System.out.println(num+" ");
count++;
}
}
return count;
}
private static boolean isKaprekarNumber(int num)
{
long square = (long) num * num;
String squareStr = String.valueOf(square);
for (int i = 1; i < squareStr.length(); i++)
{
String leftStr = squareStr.substring(0, i);
String rightStr = squareStr.substring(i);
int left = (leftStr.isEmpty()) ? 0 : Integer.parseInt(leftStr);
int right = (rightStr.isEmpty()) ? 0 : Integer.parseInt(rightStr);
if (left + right == num && left > 0 && right > 0)
{
return true;
}
}
return false;
}
}
The divide-and-conquer approach
The divide-and-conquer paradigm involves three steps at each level of the recursion:
Divide the problem into a number of subproblems that are smaller instances of the
same problem.
Conquer the subproblems by solving them recursively. If the subproblem sizes are
small enough, however, just solve the subproblems in a straightforward manner.
Combine the solutions to the subproblems into the solution for the original problem.
EXAMPLE
The merge sort algorithm closely follows the divide-and-conquer paradigm. Intuitively, it operates as follows.
Divide: Divide the n-element sequence to be sorted into two subsequences of n=2
elements each.
Conquer: Sort the two subsequences recursively using merge sort.
Combine: Merge the two sorted subsequences to produce the sorted answer.
| 1 | Magic number | CLICK |
| 2 | Happy number | CLICK |
| 3 | Fibonacci series | CLICK |
| 4 | Check twin prime from a series | CLICK |
| 5 | Armstrong number | CLICK |
| 6 | Automorphic number | CLICK |
| 7 | decimal to binary conversion | CLICK |
| 8 | a+a/2! +a/3! +a/4! +.... n th term | |
| 9 | neon number in java | CLICK |
| 10 | KaprekarNumbers | CLICK |
| 11 | Fascinating Number | CLICK |
| 12 | square Matrix | CLICK |
| 13 | string having repeating characters | CLICK |
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