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Remove the duplicate number from a given integer array or list.

Removing the duplicate elements from an array is the same as printing the unique elements of an array.

Notes:- If we write 

            boolean[ ]  flag = new boolean[ size ] ;

            in java, it creates an array of booleans where false present in all positions by default.

            We don't have to assign value to flag array elements exclusively.

 Java

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 public class RemoveDuplicate{
     public static void main(String []args){
        int[] arr = {1, 2, 3, 6, 3, 3, 3, 4, 2};
        boolean[] flag = new boolean[arr.length];
        for(int i=0; i<arr.length; i++)
            if(!flag[i])
                for(int j=i+1; j<arr.length; j++)
                    if(arr[i]==arr[j])
                        flag[j] = true;

        for(int i=0; i<arr.length; i++)
            if(!flag[i])
                System.out.print(arr[i]+" ");
        
     }
 }

Python

arr = [1, 2, 3, 6, 3, 3, 3, 4, 2]
flag = [False]*len(arr)
for i in range(0,len(arr)):
    if not flag[i]:
        for j in range(i+1,len(arr)):
            if arr[i]==arr[j]:
                flag[j] = True

for i in range(0,len(arr)):
    if not flag[i]:
        print(arr[i],end=" ")