Algorithms/Find maximum/Python method 2

Python (2.6) source code.

def findMax(a):

    length = len(a)

    if length == 0 :
        return 0

    elif length == 1 :
        return a[0]

    elif length == 2 :

        if a[0] > a[1] :
            return a[0] 
        else :
            return a[1]

    half = length / 2

    list_A = a[:half]
    list_B = a[half:]

    max_A = findMax(list_A)
    max_B = findMax(list_B)

    if max_A > max_B :
        return max_A
    else :
        return max_B