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How to count unique elements in the array using java?
The interface Set does not allow duplicate elements, therefore, create a set object and try to add each element to it using the add() method in case of repetition of elements this method returns false −
If you try to add all the elements of the array to a Set, it accepts only unique elements −
Example
import java.util.Arrays;
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;
public class CountingUniqueElements {
public static void main(String args[]) {
Scanner sc = new Scanner(System.in);
System.out.println("Enter the size of the array that is to be created ::");
int size = sc.nextInt();
int count = 0;
int[] myArray = new int[size];
System.out.println("Enter the elements of the array ::");
for(int i = 0; i<size; i++) {
myArray[i] = sc.nextInt();
}
System.out.println("The array created is :: "+Arrays.toString(myArray));
System.out.println("indices of duplicate elements in the array are elements :: ");
Set set = new HashSet();
for(int i = 0; i<myArray.length; i++) {
if(set.add(myArray[i])) {
count++;
System.out.println("Index :: "+i+" Element :: "+myArray[i]);
}
}
}
}
Output
Enter the size of the array that is to be created :: 6 Enter the elements of the array :: 45 45 45 69 32 69 The array created is :: [45, 45, 45, 69, 32, 69] indices of duplicate elements in the array are elements :: Index :: 0 Element :: 45 Index :: 3 Element :: 69 Index :: 4 Element :: 32
Updated on: 30-Jul-2019
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