Algorithm NaiveMajorityElement(A: array, N: integer)
Input:
   An array A of size N.
Output:
   The majority element of A, if exist. Otherwise, null.
   
threshold <- N div 2 + 1;   // div: integer division.

for (i=0 to n-1)
    //   if A[i] is a majority element then
    count <- 0;  
    for (j-0 to n-1)
        if (A[i] == A[j]) count++;
    end for
    if (count >= threshold) // it is a majority element.
        return A[i];
end for;

return null;

O(n2)

Best case: one iteration; A[0] is the majority element.
Worst case: N iterations; no majority element.