Move all the negative elements to one side of the array in Java

April 13, 2022

Move all negative elements to one side of the array  in Java

Here, in this page we will discuss the program to move all negative elements to one side of the array in Java . We use the concept of two pointers to do so . We are giving with the size of the array along with array elements.We have to print array as desired

Move all negative elements to one side

Algorithm :

  • Let ‘j’ point to the leftmost positive element in the array. Initially, we set ‘j’ to point to the first element.
  • Iterate over the array:
  • Let ‘i’ be the index of the current element.
  • If the current element is negative:
  • If ‘i’ not equal to ‘j’, then swap the ith and jth elements.
  • Increment ‘j’ by 1.
  • Return the resulting array

Java Code

Run 

import java.util.*;
public
class Main {
    public
    static void shift(int[] arr) {
        int j = 0;
        for (int i = 0; i < arr.length; i++) {
            if (arr[i] < 0) {
                if (i != j) swap(arr, i, j);
                j++;
            }
        }
        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i] + " ");
        }
    }
    // used for swapping ith and jth elements of array
    public
    static void swap(int[] arr, int i, int j) {
        int temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }
    public
    static void main(String[] args) throws Exception {
        

        int[] arr = new int[]{ -1,0,3,1,-4}; 
       
        shift(arr);
    }
}

Output :

-1 -2 4 2 2

6 comments on “Move all the negative elements to one side of the array in Java”


  • mstofficial19

    public static void move(int arr[]){
    int i=0;
    int k=arr.length-1;
    while(i<k){
    if(arr[i]=0){
    int temp=arr[k];
    arr[k]=arr[i];
    arr[i]=temp;
    i++;
    k–;
    }

    else if(arr[i]>=0&&arr[k]<0){
    i++;
    k–;
    }
    else if(arr[i]<0&&arr[k]=0&&arr[k]>=0){
    i++;

    }

    }
    for(int j=0;j<arr.length;j++){
    System.out.print(arr[j]+" ");
    }
    }


  • SIVALI

    import java.util.*;

    public class Main
    {
    //P N -> SWAP and increment (l++ and r–)
    // N P -> INCREMENT(L++ , R++)
    //N N -> L++
    //P P -> R–

    static void negative(int n , int[] a ){
    int l = 0 ;
    int r = n-1 ;

    while(l 0 && a[r] < 0) {
    int temp = a[l] ;
    a[l] = a[r] ;
    a[r] = temp ;
    l++ ;
    r– ;
    }
    else if(a[l] 0) {
    l++;
    r– ;
    }
    else if(a[l] < 0 && a[r] <0){
    l++ ;
    }
    else{
    r– ;
    }

    }

    System.out.println("array is ") ;
    //for loop to print array
    for(int i=0 ; i<n ; i++){
    System.out.println(a[i]) ;
    }
    }

    public static void main(String[] args) {
    Scanner sc = new Scanner(System.in) ;
    System.out.println("enter size") ;
    int n = sc.nextInt() ;
    int[] a = new int[n] ;
    for(int i=0 ; i<n ; i++){
    a[i] = sc.nextInt() ;
    }

    negative(n,a) ;

    }
    }


  • Gyanendra

    import java.util.*;
    public class Main{
    public static void main(String[] args){
    Scanner scn=new Scanner(System.in);
    int n=scn.nextInt();
    int[] arr=new int[n];

    for(int i=0;i<n;i++){
    arr[i]=scn.nextInt();
    }

    int i=0,j=0;

    while(j<arr.length){
    if(arr[j]<0){
    int temp=arr[i];
    arr[i]=arr[j];
    arr[j]=temp;
    i++;
    j++;
    }
    else{
    j++;
    }
    }

    for(int temp: arr){
    System.out.print(temp+" ");
    }
    }
    }


  • Shyam

    public class Shiftallnegative_to_inthe_last {
    public static void shift(int[] arr) {
    int a[] = new int[arr.length];
    int j = 0;
    for (int i = 0; i 0) {
    a[j] = arr[i];
    j++;
    }
    }
    for (int i = 0; i < arr.length; i++) {
    if (arr[i] <= 0) {
    a[j]=arr[i];
    j++;
    }
    }
    for(int k=0;k<a.length;k++){
    System.out.println(a[k]);
    }

    }

    public static void swap(int []arr,int i,int j){
    int temp=arr[i];
    arr[i]=arr[j];
    arr[j]=temp;
    }

    public static void main(String[] args) {
    int a[]={-1,9,6,-2,-3,3};
    shift(a);

    }
    }