albero somma

class Albero:
    def __init__(self, val):
        self.val = val
        self.sx = None
        self.dx = None


a = Albero(8)
b = Albero(3)
c = Albero(10)
d = Albero(1)
e = Albero(6)
f = Albero(4)
g = Albero(7)
h = Albero(14)
i = Albero(13)


a.sx = b
a.dx = c
b.sx = d
b.dx = e
e.sx = f
e.dx = g
c.dx = h
h.sx = i



def sommaNodi(a):
    if a is None:
        return 0

    if a.sx is None and a.dx is None:
        return a.val

    somma = a.val

    if a.sx is not None:
        somma += sommaNodi(a.sx)

    if a.dx is not None:
        somma += sommaNodi(a.dx)

    return somma