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Java Array Exercises: Form the largest number from a given list of non negative integers

Java Array: Exercise-71 with Solution

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 said array numbers: 643210

Sample Solution:

Java Code:

import java.util.*;
public class solution {
	
 public static String  largest_Numbers(int[] num) {
        String[] array_nums = Arrays.stream(num).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[] args)
  {
    int[] nums = {1, 2, 3, 0, 4, 6};
	System.out.printf("\nOriginal array: "+Arrays.toString(nums));	
	System.out.printf("\nLargest number using the said array numbers: "+largest_Numbers(nums));
   }  
}

Sample Output:

Original array: [1, 2, 3, 0, 4, 6]
Largest number using the said array numbers: 643210

Flowchart:

Flowchart: Form the largest number from a given list of non negative integers.

Java Code Editor:

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Previous: Write a Java program to find the smallest length of a contiguous subarray of which the sum is greater than or equal to specified value. Return 0 instead.
Next: Write a Java program to find and print one continuous subarray (from a given array of integers) that if you only sort the said subarray in ascending order then the entire array will be sorted in ascending order.

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Java: Tips of the Day

Array vs ArrayLists:

The main difference between these two is that an Array is of fixed size so once you have created an Array you cannot change it but the ArrayList is not of fixed size. You can create instances of ArrayLists without specifying its size. So if you create such instances of an ArrayList without specifying its size Java will create an instance of an ArrayList of default size.

Once an ArrayList is full it re-sizes itself. In fact, an ArrayList is internally supported by an array. So when an ArrayList is resized it will slow down its performance a bit as the contents of the old Array must be copied to a new Array.

At the same time, it's compulsory to specify the size of an Array directly or indirectly while creating it. And also Arrays can store both primitives and objects while ArrayLists only can store objects.

Ref: https://bit.ly/3o8L2KH