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Java Array Exercises: Segregate all 0s on left side and all 1s on right side of a given array of 0s and 1s

Java Array: Exercise-42 with Solution

Write a Java program to segregate all 0s on left side and all 1s on right side of a given array of 0s and 1s.

Pictorial Presentation:

Java Array Exercises: Segregate all 0s on left side and all 1s on right side of a given array of 0s and 1s

Sample Solution:

Java Code:

import java.util.*;
import java.lang.*;
public class Main
{
   public static void main (String[] args) 
    {  
        int nums[] = {0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1};
        int i,  nums_size = nums.length;
        int left = 0, right = nums_size - 1;
        
        System.out.println("Original Array : "+Arrays.toString(nums));  
 
        while (left < right) 
        {
            /* While  0 at left increment left index  */
            while (nums[left] == 0 && left < right)
               left++;
 
            /* While we see 1 at right decrement right index*/
            while (nums[right] == 1 && left < right)
                right--;
 
           
            if (left < right) 
            {
                nums[left] = 0;
                nums[right] = 1;
                left++;
                right--;
            }
        }
        
       System.out.println("Array after segregation is : "+Arrays.toString(nums));  
    }
}

Sample Output:

                                                                              
Original Array : [0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1]
Array after segregation is : [0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1]

Flowchart:

Flowchart: Segregate all 0s on left side and all 1s on right side of a given array of 0s and 1s

Visualize Java code execution (Python Tutor):


Java Code Editor:

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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