majority

def majority(array, tiebreaker=None):
    n = len(array)
    if n == 0:
        return tiebreaker
    pairs = []
    if n % 2 == 1:
        tiebreaker = array[-1]
    for i in range(0, n-1, 2):
        if array[i] == array[i+1]:
            pairs.append(array[i])
    major = majority(pairs, tiebreaker )
    if major is None:
        return None
    nMajor = array.count(major)
    if 2*nMajor > n or (2*nMajor == n and major == tiebreaker ):
        return major
    return None