Find a number where it appears exactly N/2 times

Question

Here is one of my interview question. Given an array of N elements and where an element appears exactly N/2 times and the rest N/2 elements are unique

Answer 1

Algorithm RepeatedElement(a, n)

while (true) do
{
   i=Random() mod n+1; j=Random() mod n+1;
   // i and j are random numbers in the range [1,n]
   if ((i ≠ j) and a[i]=a[j])) then return;
}