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Java Array Exercises: Arrange the elements of a given array of integers where all negative integers appear before all the positive integers

Java Array: Exercise-48 with Solution

Write a Java program to arrange the elements of a given array of integers where all negative integers appear before all the positive integers.

Pictorial Presentation:

Java Array Exercises: Arrange the elements of a given array of integers where all negative integers appear before all the positive integers

Sample Solution:

Java Code:

import java.util.Arrays;

public class Main {

    public static void main(String[] args) {
        int[] nums = {-4, 8, 6, -5, 6, -2, 1, 2, 3, -11};
		System.out.println("Original Array: "+Arrays.toString(nums)); 
        sort_nums(nums);
        System.out.println("New Array: "+Arrays.toString(nums)); 
    }
    public static void sort_nums(int[] nums){
        int pos_num = 0;
        int neg_num = 0;
        int i,j;
        int max = Integer.MIN_VALUE;
        for(i=0; i<nums.length; i++){
            if(nums[i]<0) neg_num++;
            else pos_num++;
            if(nums[i]>max) max = nums[i];
        }
        max++;
        if(neg_num==0 || pos_num == 0) return;
        i=0;
        j=1;
        while(true){
            while(i<=neg_num && nums[i]<0) i++;
            while(j<nums.length && nums[j]>=0) j++;
            if(i>neg_num || j>=nums.length) break;
            nums[i]+= max*(i+1);
            swap_nums(nums,i,j);
        }

        i = nums.length-1;
        while(i>=neg_num){
            int div = nums[i]/max;
            if(div == 0) i--;
            else{
                nums[i]%=max;
                swap_nums(nums,i,neg_num+div-2); 
            }
        }

    }
    private static void swap_nums(int[] nums, int i , int j){
        int t = nums[i];
        nums[i] = nums[j];
        nums[j] = t;
    }
}

Sample Output:

                                                                              
Original Array: [-4, 8, 6, -5, 6, -2, 1, 2, 3, -11]
New Array: [-4, -5, -2, -11, 6, 6, 1, 2, 8, 3]

Flowchart:

Flowchart: Arrange the elements of a given array of integers where all negative integers appear before all the positive integers

Visualize Java code execution (Python Tutor):


Java Code Editor:

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Java: Tips of the Day

Different between parseInt() and valueOf() in java?

Well, the API for Integer.valueOf(String) does indeed say that the String is interpreted exactly as if it were given to Integer.parseInt(String). However, valueOf(String) returns a new Integer() object whereas parseInt(String) returns a primitive int.

If you want to enjoy the potential caching benefits of Integer.valueOf(int), you could also use this eyesore:

Integer k = Integer.valueOf(Integer.parseInt("123"))

Now, if what you want is the object and not the primitive, then using valueOf(String) may be more attractive than making a new object out of parseInt(String) because the former is consistently present across Integer, Long, Double, etc.

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