Question

Suppose you are provided with an array of integer values. Write pseudocode for a program to determine how many unique values are in the array. Your solution should require time that is linearithmic in the size of the array.

(For example, if the array contains the values {1,3,4,1,2}, the answer is "4", because the array contains the values 1, 2, 3, and 4)

Answer 1

Here I am providing the answer for the above question:

public class UniqueCount
{  
   void countUnique(int a[], int size)
   {
       int count=0;
   for (int i = 0; i < size; i++)
   {
   int j;
   for (j = 0; j < i; j++) //each elements is compared with current element a[i].
       if (a[i] == a[j]) //if any match occur we will break the loop
           break;
  
   if (i == j) //if no match occur in the particular iteration the i,j values will be same.
   {
       count++; //so now increase the count.
   }
      
   }
   System.out.println("\nCount of Unique Values:"+count);
   }
   public static void main (String[] args)
   {
       UniqueCount c=new UniqueCount();
   int a[] = {1,3,4,1,2,5,2,7,3,9,8,12,45,76};
   int size = a.length;
   c.countUnique(a, size);
  
   }

}

Output:

Hoping that the above code will help you...Thank you...