Tech Jargon - Decoded

// Program to print 2D array in a wave format
class PrintArray{
    public static void main(String args[]){
        int [][] arr={
            {1,2,3,10},
            {4,5,6,20},
            {7,8,9,30}
        };
       for(int col=0;col<arr[0].length;col++){
        if(col%2==0){
            for(int row=0;row<arr.length;row++){
                System.out.print(arr[row][col]+" ");
            }
        }
        else
        {
            for(int row=arr.length-1;row>=0;row--){
                System.out.print(arr[row][col]+" ");
            }
        }
       }
    }
}

//Leetcode 1480,running sum of 1d array (brute force algorithm)
class Solution {
    public int[] runningSum(int[] nums) {
        int runningSum[]=new int[nums.length];

        for(int i=0;i<nums.length;i++){
           int sum=0;
           for(int j=0;j<=i;j++){
               sum=sum+nums[j];
           }
           runningSum[i]=sum;
        }
        return runningSum;
    }
}

// Program to add two arrays and store res in an array list 
import java.util.ArrayList;
class AddArrays{
    public static void main(String args[]){
        int arr1[]={8,4,6};
        int arr2[]={2,7,3,5,4};
        ArrayList<Integer> res=new ArrayList<>();
        int i=arr1.length-1;
        int j=arr2.length-1;
        int carry=0;
        while(i>=0 || j>=0)
        {
            int sum=0;
            if(i>=0){
                sum=sum+arr1[i];
            }
            if(j>=0){
                sum=sum+arr2[j];
            }
            sum=sum+carry;
            int rem=sum%10;
            carry=sum/10;
            res.add(0,rem);
            i--;
            j--;
        }
        if(carry!=0){
            res.add(0,carry);
        }
        System.out.println(res);
    }
}

// Program to print intersected elements of two sorted arrays of different size using array list
import java.util.ArrayList;
class ArraysIntersection{
    public static void main(String args[]){
      int arr1[]={10,20,30,40,50};
      int arr2[]={5,10,15,30,40,45,50,55};
      ArrayList<Integer> res=new ArrayList<>(); 
      int i,j;
      i=0;
      j=0;
      while(i<arr1.length && j<arr2.length){
        if(arr1[i]<arr2[j]){
            i++;
        }
        else if(arr1[i]>arr2[j]){
            j++;
        }
        else
        {
            res.add(arr1[i]);
            i++;
            j++;
        }
      }
      System.out.println("Intersection of arr1 and arr2 : "+res);
    }
}

// Program to rotate an array 
public class RotateArray{
    public static void main(String args[])
    {
        int[] arr={1,2,3,4,5};
        rotateArr(arr,4);
        for(int i=0;i<arr.length;i++){
        System.out.print(arr[i]+" ");
    }
    }
    public static void rotateArr(int[] a,int k)
    {
        k=k%a.length;
        if(k<0){
            k=k+a.length;
        }
        int temp;
        for(int r=1;r<=k;r++){
            temp=a[a.length-1];
            for(int i=a.length-1;i>=1;i--){
                a[i]=a[i-1];
            }
            a[0]=temp;
        }
    }
}

// Program to find maximum element of an array 
public class MaxElement{
    public static void main(String args[]){
        int[] arr={20,12,21,34,18};
        int max=findMax(arr);
        System.out.println("The maximum element of the given array is: "+max);
    }
    public static int findMax(int[] a){
        int maxElement=a[0];
        for(int i=1;i<a.length;i++)
        {
            if(maxElement<a[i])
            {
                maxElement=a[i];
            }
        }
        return maxElement;
    }
}

// Program to find minimum element of an array 
public class MinElement{
    public static void main(String args[]){
        int[] arr={10,22,11,13,18};
        int min=findMin(arr);
        System.out.println("The minimum element of given array is "+min);
    }
    public static int findMin(int[] a){
        int minElement=a[0];
        for(int i=1;i<a.length;i++)
        {
            if(minElement>a[i])
            {
                minElement=a[i];
            }
        }
        return minElement;
    }
}

// Program to print Amstrong numbers in a given range 

import static java.lang.Math.pow;
public class PrintAmstrong{
    public static void main(String args[]){
        for(int i=100;i<=1000;i++)
        {
            if(isAmstrong(i)){
                System.out.println(i+" is an Amstrong number");
            }
        }
    }
    public static boolean isAmstrong(int num){
        int origNum=num;
        int digitCount=countDigits(num);
        int sum=0;
        while(num>0){
            int rem=num%10;
            sum+=Math.pow(rem,digitCount);
            num=num/10;
        }
        return origNum==sum;
    }
    public static int countDigits(int number){
        int count=0;
        while(number>0){
            number=number/10;
            count++;
        }
        return count;
    }
}

// Program to check wheather a number is amstrong or not
import static java.lang.Math.pow;
public class AmstrongOrNot{
    public static void main(String args[]){
        System.out.println(isAmstrong(153));
    }
    public static boolean isAmstrong(int num){
        int origNum=num;
        int digitCount=countDigits(num);
        int sum=0;
        while(num>0){
            int rem=num%10;
            sum+=Math.pow(rem,digitCount);
            num=num/10;
        }
        return origNum==sum;
    }
    public static int countDigits(int number){
        int count=0;
        while(number>0){
            number=number/10;
            count++;
        }
        return count;
    }
}

// Program to print fibonacci sequence using function 
public class Fibonacci{
    public static void main(String args[]){
        int n=10;
        printFibonacci(n);
    }
    public static void printFibonacci(int n){
        int firstNum=0,secondNum=1;
        int temp;
        for(int i=0;i<n;i++){
            System.out.println(firstNum+" ");
            temp=firstNum+secondNum;
            firstNum=secondNum;
            secondNum=temp;
        }
    }
}

// Program to calculate factorial of a number 
public class GetFactorial{
    public static void main(String args[]){
        int num=5;
        int res=calcFact(num);
        System.out.println("Factorial of "+num+" is "+res);
    }
    public static int calcFact(int number){
        int fact=1;
        for(int i=1;i<=number;i++){
            fact=fact*i;
        }
        return fact;
    }
}

// Program to add two numbers using functions 
public class AddTwoNums{
    public static void main(String args[]){
        int res;
        res=addTwoNums(10,20);
        System.out.println("Result:"+res);
        }
        public static int addTwoNums(int num1,int num2){
            return num1+num2;
        }
}

// Program to print Hello world using function
public class HelloWorld{
    public static void main(String args[]){
        sayHello();
    }
    public static void sayHello(){
        System.out.println("Hello World");
    }
}

public static void main(String args[]) {
        int n = 7; // total number of rows
        int totalRows = n;
        int spaces = n - 2; // initial number of spaces
        int stars = 1; // initial number of stars

        for (int row = 1; row <= totalRows; row++) {
            // Print stars in increasing order
            for (int starCount = 1; starCount <= stars; starCount++) {
                System.out.print("*");
            }

            // Print spaces
            for (int spaceCount = 1; spaceCount <= spaces; spaceCount++) {
                System.out.print(" ");
            }

            // Adjust the number of stars for the second set
            int secStars = stars;
            if (row == totalRows / 2 + 1) {
                secStars = stars - 1;
            }

            // Print the second set of stars
            for (int starCount = 1; starCount <= secStars; starCount++) {
                System.out.print("*");
            }

            System.out.println();

            // Adjust the number of stars and spaces for the next row
            if (row <= totalRows / 2) {
                stars++;
                spaces -= 2;
            } else {
                stars--;
                spaces += 2;
            }
        }
    }
}

// *     *
// **   **
// *** ***
// *******
// *** ***
// **   **
// *     *
public class Pattern6{
    public static void main(String args[]){
        int n=7;
        int totalRows=n;
        int spaces=n-2;
        int stars=1;
        for(int row=1;row<=totalRows;row++){
            for(int starCount=1;starCount<=stars;starCount++){
                System.out.print("*");
            }
            for(int spaceCount=1;spaceCount<=spaces;spaceCount++){
                System.out.print(" ");
            }
            int secStars=stars;
            if(row == totalRows/2+1){
                secStars=stars-1;
            }
            for(int starCount=1;starCount<=secStars;starCount++){
                System.out.print("*");
            }
            System.out.println();
            if(row<= totalRows/2){
                stars++;
                spaces-=2;
            }
            else{
                stars--;
                spaces+=2;
            }
        }
    }
}

// *******
// *** ***
// **   **
// *     *
public class Pattern5{
    public static void main(String args[]){
        int n=4;
        int totalRows=n;
        int spaces=1;
        int stars=n-1;
        for(int row=1;row<=2*n-1;row++){
            System.out.print("*");
        }
        System.out.println();
        for(int row=2;row<=totalRows;row++){
            for(int countStars=1;countStars<=stars;countStars++){
                System.out.print("*");
            }
            for(int countSpaces=1;countSpaces<=spaces;countSpaces++){
                System.out.print(" ");
            }
            for(int countStars=1;countStars<=stars;countStars++){
                System.out.print("*");
            }
            System.out.println();
            stars--;
            spaces+=2;
        }
    }
}

//    *
//   ***
//  *****
// *******
//  *****
//   ***
//    *
public class Pattern4{
    public static void main(String args[]){
        int n=7;
        int totalRows=n;
        int spaces=n/2;
        int stars=1;
        for(int row=1;row<=totalRows;row++){
            for(int spaceCount=1;spaceCount<=spaces;spaceCount++){
                System.out.print(" ");
            }
            for(int starCount=1;starCount<=stars;starCount++){
                System.out.print("*");
            }
            System.out.println();
            if(row <= totalRows/2)
            {
                spaces--;
                stars+=2;
            }
            else{
                spaces++;
                stars-=2;
            }
        }
    }
}