Java program for removing duplicate element in an array

November 26, 2021

Remove Duplicates elements

Here is a program to remove duplicate elements in an array  is discussed here. Given an array, all the duplicate elements of the array are removed.

For example, consider the array

Example (sorted)

Input: arr = {1, 2, 3, 4, 4}

Output: arr = {1, 2, 3, 4}

remove duplicate elements in java
remove duplicate elements in java

      Algorithm

  • Input the number of elements of the array.
  • Input the array elements.
  • Repeat from i = 1 to n
  • – if (arr[i] != arr[i+1])
  • – temp[j++] = arr[i]
  • – temp[j++] = arr[n-1]
  • Repeat from i = 1 to j
  • – arr[i] = temp[i]
  • return j.

 

Java Code

import java.util.*;
public class Main{
public static int removeduplicates(int a[], int n)
{
if (n == 0 || n == 1) {
return n;
}

// creating another array for only storing
// the unique elements
int[] temp = new int[n];
int j = 0;

for (int i = 0; i < n - 1; i++) {
if (a[i] != a[i + 1]) {
temp[j++] = a[i];
}
}

temp[j++] = a[n - 1];

// Changing the original array
for (int i = 0; i < j; i++) {
a[i] = temp[i];
}

return j;
}
public static void main(String[] args)
{
Scanner s = new Scanner(System.in);
System.out.print("Enter no. of elements you want in array:");
int n;
n = s.nextInt();

int a[] = new int[n];
System.out.println("Enter all the elements:");
for(int i = 0; i < n; i++)
{
a[i] = s.nextInt();
}

n = removeduplicates(a, n);

// Printing The array elements
for (int i = 0; i < n; i++)
System.out.print(a[i] + " ");
}

}

Output

Enter size of an array 
6
Enter elements in an array 
1
2
3 
3 
4 
5 
After removing duplicate elements 1,2,3,4,5

8 comments on “Java program for removing duplicate element in an array”


  • Adarsh kumar

    size=int(input())
    arr=list()
    for i in range(size):
    arr.append(int(input()))
    arr.sort()
    l=list(dict.fromkeys(arr))
    print(*l)


  • Mahesh

    int[]a={1,2,42,13,3,55,3,23,55,45,6,25,5,5,53,34,34,33,35};
    Arrays.sort(a);
    boolean []vis=new boolean[a.length];
    for(int i=0;i<a.length-1;i++){
    if(a[i]==a[i+1]){
    vis[i]=true;
    //vis[i+1]=true;
    }
    }
    for(int i=0;i<a.length;i++){
    if(!vis[i]){
    System.out.print(a[i]+" ");
    }
    }


  • DHANANJAY

    ————————————————-
    #Code in Python
    #1. Using dict.formkeys()
    n = list(map(int,input().strip().split()))
    m = list(dict.fromkeys(n))
    print(*m)
    ——————————————————————-
    #2. Using set operator
    n = list(map(int,input().strip().split()))
    m = list(set(n))
    print(*m)


  • DHANANJAY

    ————————————————-
    #Code in Python
    #1. Using dict.formkeys()
    n = list(map(int,input().strip().split()))
    m = list(dict.fromkeys(n))
    print(*m)

    #Using set operator
    n = list(map(int,input().strip().split()))
    m = list(set(n))
    print(*m)


  • Rohit

    #———program for removing duplicate element in an array using python———-
    arr=list(map(int, input().split()))
    arr1=[]

    #——-traverse the array list——–
    for i in arr:
    if i not in arr1:
    arr1.append(i)
    print(*arr1)


  • SRT

    #include
    int main()
    {
    int count, i, j, n;
    int arr[100];
    scanf(“%d”, &n);
    for(i = 0; i<n; i++)
    {
    scanf("%d", &arr[i]);
    }
    for(i = 0; i<n; i++)
    { //finding non repeating character//
    count = 0;
    for(j = 0; j<n; j++)
    {
    if(arr[i] == arr[j])
    {
    if(i!=j)
    {
    count++;
    }
    }
    }

    if(count == 0)
    {
    printf(" %d", arr[i]); // printing above code//
    }
    // finding repeating character //
    count = 0;
    for(j = i + 1; j<n; j++)
    {
    if(arr[i] == arr[j])
    {
    if(i!=j)
    {
    count++;
    }
    }
    }

    if(count == 1)
    {
    printf(" %d", arr[i]); // printing above code//
    // with space given it will print all code in one line//
    }

    }
    return 0;
    }


  • Ajay

    #include
    using namespace std;
    int main()
    {
    int a[50],n,temp;
    int i,j;
    cout<<" enter size "<>n;
    cout<<" \n enter elements \n";
    for(i=0;i>a[i];
    }
    for(i=0;i<n;i++)
    {
    for(j=i+1;ja[j])
    {
    temp = a[i];
    a[i]=a[j];
    a[j]=temp;
    }
    }
    }
    int temp2[50];
    int k=0;
    for(i=0;i<n-1;i++)
    {
    if(a[i]!= a[i+1])
    {
    temp2[k++]=a[i];
    }
    }
    temp2[k++]=a[n-1];
    cout<<"duplicate removed array =";
    for(i=0;i<k;i++)
    {
    cout<<" "<<temp2[i];
    }
    return 0;
    }


    • Rahul

      In Python

      lst=list(map(int,input().split()))
      uni_lst=list(set(lst))
      print(*uni_lst)