Answer to Question #318452 in Java | JSP | JSF for lolo

Question

1.      Write a Java program to rearrange a given array of unique elements such that every second element of the array is greater than its left and right elements.  

 

Example:

Input :

nums= { 1, 2, 4, 9, 5, 3, 8, 7, 10, 12, 14 }

Output:

Array with every second element is greater than its left and right elements:

[1, 4, 2, 9, 3, 8, 5, 10, 7, 14, 12]

 

2.      Write a Java program to form the largest number from a given list of non-negative integers.  

 

Example:

Input :

nums = {1, 2, 3, 0, 4, 6}

Output:

Largest number using the given array numbers: 643210

 

3.      Write a Java program to shuffle a given array of integers.

 

 

4.      Write a Java program to find maximum product of two integers in a given array of integers.  

 

Example:

Input :

nums = { 2, 3, 5, 7, -7, 5, 8, -5 }

Output:

Pair is (7, 8), Maximum Product: 56

Answer 1

import java.util.Arrays;

public class Program1 {
    private static void swap(int[] elements, int i, int j) {
        int num = elements[i];
        elements[i] = elements[j];
        elements[j] = num;
    }
    public static void rearrangeArray(int[] elements)
    {
        for (int i = 1; i < elements.length; i += 2)
        {
            if (elements[i - 1] > elements[i]) {
                swap(elements, i - 1, i);
            }

            if (i + 1 < elements.length && elements[i + 1] > elements[i]) {
                swap(elements, i + 1, i);
            }
        }
    }
    public static void main(String ars[]){
        int[] nums= { 1, 2, 4, 9, 5, 3, 8, 7, 10, 12, 14 };
        System.out.println("Original array: " + Arrays.toString(nums));
        rearrangeArray(nums);
        System.out.println("Array with every second element is greater than its left and right elements: \n" + Arrays.toString(nums));
    }
}
import java.util.Arrays;

public class Program2 {
    public static String  largestNumbers(int[] elements) {
        String[] array_nums = Arrays.stream(elements).mapToObj(String::valueOf).toArray(String[]::new);
        Arrays.sort(array_nums, (String str1, String str2) -> (str2 + str1).compareTo(str1 + str2));
        return Arrays.stream(array_nums).reduce((a, b) -> a.equals("0") ? b : a + b).get();
    }
    public static void main(String ars[]){
        int[] nums = {1, 2, 3, 0, 4, 6};
        System.out.print("\nOriginal array: " + Arrays.toString(nums));
        System.out.print("\nLargest number using the said array numbers: " + largestNumbers(nums));
    }
}
import java.util.Arrays;
import java.util.Random;

public class Program3 {
    private static void swap(int[] elements, int i, int j) {
        int num = elements[i];
        elements[i] = elements[j];
        elements[j] = num;
    }
    public static void shuffle(int elements[]){
        for (int i = elements.length - 1; i >= 1; i--)
        {
            Random rand = new Random();
            int j = rand.nextInt(i + 1);
            swap(elements, i, j);
        }
    }
    public static void main(String ars[]){
        int[] nums = { 1, 2, 3, 4, 5, 6 };
        System.out.println("Original Array: " + Arrays.toString(nums));
        shuffle(nums);
        System.out.println("Shuffle Array: " + Arrays.toString(nums));
    }
}
import java.util.Arrays;

public class Program4 {
    public static void findMaxProduct(int[] elements)
    {
        int max_pair_product = Integer.MIN_VALUE;
        int max_i = -1, max_j = -1;
        for (int i = 0; i < elements.length - 1; i++)
        {
            for (int j = i + 1; j < elements.length; j++)
            {
                if (max_pair_product < elements[i] * elements[j])
                {
                    max_pair_product = elements[i] * elements[j];
                    max_i = i;
                    max_j = j;
                }
            }
        }
        System.out.print("Pair is (" + elements[max_i] + ", " + elements[max_j] + "), Maximum Product: " + (elements[max_i] * elements[max_j]));
    }
    public static void main(String ars[]){
        int[] nums = { 2, 3, 5, 7, -7, 5, 8, -5 };
        System.out.println("\nOriginal array: " + Arrays.toString(nums));
        findMaxProduct(nums);
    }
}