﻿ Java - Sort negatives elements before positives in an array

# Java: 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 an array of integers so that all negative integers appear before all positive integers.

Pictorial Presentation: Sample Solution:

Java Code:

``````// Import the necessary Java utility class for working with arrays.
import java.util.Arrays;

// Define the Main class.
public class Main {

// The main method for executing the program.
public static void main(String[] args) {
// Define an array of integers.
int[] nums = {-4, 8, 6, -5, 6, -2, 1, 2, 3, -11};

// Print the original array.
System.out.println("Original Array: " + Arrays.toString(nums));

// Call the sort_nums method to modify the array.
sort_nums(nums);

// Print the modified array.
System.out.println("New Array: " + Arrays.toString(nums));
}

// Method to sort the numbers in the array based on their signs.
public static void sort_nums(int[] nums){
int pos_num = 0;
int neg_num = 0;
int i, j;
int max = Integer.MIN_VALUE;

// Count the positive and negative numbers and find the maximum 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 there are no negative or positive numbers, return.
if(neg_num == 0 || pos_num == 0) return;

i = 0;
j = 1;

// Reorder the array.
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;

// Adjust the values to their original range.
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);
}
}
}

// Method to swap elements in the array.
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: Java Code Editor:

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