Making entire row and column of matrix to zero if one element is zero | alternative approach

Given a matrix if an element in the matrix is 0 then you will have to set its entire column and row to 0 and then return the matrix.

 

/**

 * Given a matrix if an element in the matrix is 0 then you will have to set its entire column and row to 0 and then return the matrix.

 */

package com.striver.sde.practice;

import java.util.ArrayList;

import java.util.List;

/**

 * @author apple

 *

 */

public class MatrixZero {

/**

* @param args

*/

public static void main(String[] args) {

int[][] input = { { 1, 1, 1 }, { 1, 0, 1 }, { 1, 1, 1 } };

MatrixZero m = new MatrixZero();

// m.findSolution(input);

m.findSolution2(input);

}

private void findSolution2(int[][] input) {

int len = input.length;

List rows = new ArrayList<>();

List cols = new ArrayList<>();

for (int row = 0; row < len; row++) {

for (int col = 0; col < len; col++) {

if (input[row][col] == 0) {

rows.add(row);

cols.add(col);

}

}

}

for (int row = 0; row < len; row++) {

for (int col = 0; col < len; col++) {

if(rows.contains(row)) {

input[row][col] =0;

}

if(cols.contains(col)) {

input[row][col] =0;

}

}

}

System.out.println(input);

}

private void findSolution(int[][] input) {

int[][] output = input.clone();

int len = input.length;

for (int row = 0; row < len; row++) {

for (int col = 0; col < len; col++) {

if (input[row][col] == 0) {

modifyMatrix(row, col, output, len);

}

}

}

}

private void modifyMatrix(int row, int col, int[][] output, int len) {

if (row == 0) {

int r = row;

while (r < len) {

output[r][col] = 0;

r = r + 1;

}

} else if (row == len) {

int r = row;

while (r >= 0) {

output[r][col] = 0;

r = r - 1;

}

} else {

}

}

}

Spiral unwinding a matrix interview question solved java source code

To unwind a matrix spirally to an array.

/**
 * Unwinding a matrix in java
 * Tested a 5 x 5 matrix
 */
package com.konzern.solution;

/**
 * @author Arjun Babu
 *
 */
public class Unwinding {

/**
* @param amazon
*/
public static void main(String[] hematcs) {
Unwinding unwindMatrix = new Unwinding();
int[][] matrix = unwindMatrix.getInput();
unwindMatrix.display(matrix);
int[] value = unwindMatrix.unwindMatix(matrix);
}

private void display(int[][] matrix) {
System.out.println("The Input Matrix \n");
int len = matrix.length;
for (int i = 0; i < len; i++) {
for (int j = 0; j < len; j++) {
System.out.print(matrix[i][j] + "\t");
}
System.out.println();
}

}

private int[] unwindMatix(int[][] matrix) {
System.out.println("\nThe Output Array \n");
int len = matrix.length;
int loopCount = len * len;
int data[] = new int[loopCount];
int flag = 0;
int maxRow = len - 1;
int maxCol = len - 1;
int minRow = 0;
int minCol = 0;
int row = 0;
int col = 0;
for (int i = 0; i < loopCount; i++) {
data[i] = matrix[row][col];
System.out.print(data[i] + " ");
switch (flag) {
case 0:
col = col + 1;
if (col > maxCol) {
col = maxCol;
row = row + 1;
minRow++;
flag = 1;
}
break;
case 1:
row = row + 1;
if (row > maxRow) {
row = maxRow;
col--;
maxCol--;
flag = 2;
}
break;
case 2:
col = col - 1;
if (col < minCol) {
row = row - 1;
col = col + 1;
maxRow--;
flag = 3;
}
break;

case 3:
row = row - 1;
if (row < minRow) {
row = row + 1;
col = col + 1;
minCol++;
flag = 0;
}
break;
default:
break;
}
}
return data;
}

private int[][] getInput() {
int matrix[][] = { { 1, 2, 3, 4, 5 }, { 6, 7, 8, 9, 10 }, { 11, 12, 13, 14, 15 }, { 16, 17, 18, 19, 20 }, { 21, 22, 23, 24, 25 } };
return matrix;
}
}

The Input Matrix 

1 2 3 4 5

6 7 8 9 10

11 12 13 14 15

16 17 18 19 20

21 22 23 24 25

The Output Array 

1 2 3 4 5 10 15 20 25 24 23 22 21 16 11 6 7 8 9 14 19 18 17 12 13 

Traffic Light in java

Traffic Light program in java

Traffic light in java source code

package test;


import java.awt.*;
import javax.swing.*;
import java.awt.event.*;


public class TrafficLight extends JFrame implements ActionListener {
    JButton buttonRed, buttonYellow, buttonGreen;

      Signal green = new Signal(Color.green);
      Signal yellow = new Signal(Color.yellow);
      Signal red = new Signal(Color.red);

    public TrafficLight(){
        super("Java Traffic Light Program");
        getContentPane().setLayout(new GridLayout(2, 1));
        buttonRed = new JButton("Red");
        buttonYellow = new JButton("Yellow");
        buttonGreen = new JButton("Green");
        buttonRed.addActionListener(this);
        buttonYellow.addActionListener(this);
        buttonGreen.addActionListener(this);      

        green.turnOn(false);
        yellow.turnOn(false);
        red.turnOn(true);

        JPanel trafficPanel = new JPanel(new GridLayout(3,1));
        trafficPanel.add(red);
        trafficPanel.add(yellow);
        trafficPanel.add(green);
        JPanel lightPanel = new JPanel(new FlowLayout());
        lightPanel.add(buttonRed);
        lightPanel.add(buttonYellow);
        lightPanel.add(buttonGreen);

        getContentPane().add(trafficPanel);
        getContentPane().add(lightPanel);
        pack();
        }


    public static void main(String[] args){
        TrafficLight trafficLight = new TrafficLight();      
        trafficLight.setVisible(true);
    }  
    public void actionPerformed(ActionEvent e){      
        if (e.getSource() == buttonRed){
            green.turnOn(false);          
            yellow.turnOn(false);
            red.turnOn(true);
        } else if (e.getSource() == buttonYellow){
            yellow.turnOn(true);          
            green.turnOn(false);
            red.turnOn(false);
        } else if (e.getSource() == buttonGreen){
            red.turnOn(false);          
            yellow.turnOn(false);
            green.turnOn(true);
        }
    }
}  
class Signal extends JPanel{

    Color on;
    int radius = 40;
    int border = 10;
    boolean change;

    Signal(Color color){
        on = color;
        change = true;
    }

    public void turnOn(boolean a){
        change = a;
        repaint();      
    }

    public Dimension getPreferredSize(){
        int size = (radius+border)*2;
        return new Dimension( size, size );
    }

    public void paintComponent(Graphics graphics){
        graphics.setColor( Color.black );
        graphics.fillRect(0,0,getWidth(),getHeight());

        if (change){
            graphics.setColor( on );
        } else {
            graphics.setColor( on.darker().darker().darker() );
        }
        graphics.fillOval( border,border,2*radius,2*radius );
    }
}

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Cryptography in java

Java Cryptography

 import javax.crypto.Cipher;
   import javax.crypto.BadPaddingException;
   import javax.crypto.IllegalBlockSizeException;
   import javax.crypto.KeyGenerator;
   import java.security.Key;
   import java.security.InvalidKeyException;

   public class LocalEncrypter {

        private static String algorithm = "DESede";
        private static Key key = null;
        private static Cipher cipher = null;

        private static void setUp() throws Exception {
            key = KeyGenerator.getInstance(algorithm).generateKey();
            cipher = Cipher.getInstance(algorithm);
        }

        public static void main(String[] args)
           throws Exception {
            setUp();
            if (args.length !=1) {
                System.out.println(
                  "USAGE: java LocalEncrypter " +
                                         "[String]");
                System.exit(1);
            }
            byte[] encryptionBytes = null;
            String input = args[0];
            System.out.println("Entered: " + input);
            encryptionBytes = encrypt(input);
            System.out.println(
              "Recovered: " + decrypt(encryptionBytes));
        }

        private static byte[] encrypt(String input)
            throws InvalidKeyException,
                   BadPaddingException,
                   IllegalBlockSizeException {
            cipher.init(Cipher.ENCRYPT_MODE, key);
            byte[] inputBytes = input.getBytes();
            return cipher.doFinal(inputBytes);
        }

        private static String decrypt(byte[] encryptionBytes)
            throws InvalidKeyException,
                   BadPaddingException,
                   IllegalBlockSizeException {
            cipher.init(Cipher.DECRYPT_MODE, key);
            byte[] recoveredBytes =
              cipher.doFinal(encryptionBytes);
            String recovered =
              new String(recoveredBytes);
            return recovered;
          }
   }

Merry Christmas and happy new year wishes to all visitors +belazy


Up helly aa fire festival

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Find Prime Number in java

how to determine prime number in java

package prime Algorithm.Testing;


import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

/**
 *java practical question
 * @author joseph
 */

/**
 * @author Samsung Galaxy S4
 *
 */
public class PrimeOrNot {

    /**
     * @param args
     */
      static int i,num,flag=0;
   
    public static void main(String[] Lumina) {
        // TODO Auto-generated method stub
   
        System.out.println(" To find prime number in java : enter the integer no:");
       BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
       try {
         num=Integer.parseInt(br.readLine());
    } catch (NumberFormatException phpexp) {
        // TODO Auto-generated catch block
        phpexp.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
       for(i=2;i           if(num%2==0)
           {
               flag=1;break;
           }
       }
       if(flag==1)
           System.out.println("Number is not prime");
       else
           System.out.println("Number is  prime"); 
    }

}
 



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How to print matrix in java

Matrix Manipulation in java

Description : To print sum of all values of matrix in java


 import java.util.Scanner;


/**
* +belazy 
*/

/**
* @author BlackBery
*
*/
public class MatrixDiagonal {

private int [][]matrix = null;
private Scanner sc = null;

public MatrixDiagonal() {
matrix = new int[3][3];
}

public static void main(String[] args) {
MatrixDiagonal md = new MatrixDiagonal();
md.getMatrixValues();
md.showMatrix();
md.computeValue();
}

private void computeValue() {

int sum = 0;

for(int row = 0; row < 3 ; row ++){
for(int col =0; col col){
sum = sum + matrix[row][col];
}

}
}
System.out.println(sum);

}

private void showMatrix() {
for(int row = 0; row < 3 ; row ++){
for(int col =0; col < 3; col ++ ){
System.out.print(matrix[row][col]+"\t");
}
System.out.println();
}

}

private void getMatrixValues() {
sc = new Scanner(System.in);
System.out.println(" Enter values ");

for(int row = 0; row < 3 ; row ++){
for(int col =0; col < 3; col ++ ){
matrix[row][col] = sc.nextInt();
}
}

}

}