最佳二叉排序树

class n:
    def __init__(self,d,L=None,R=None):
        self.d = d
        self.l = L
        self.r = R
def f(L):
    Len = len(L)
    if 1 == Len:
        return n(L[0])
    elif 2 == Len:
        return n(L[1], n(L[0]))
    else:
        return n(L[Len//2], f(L[:Len//2]), f(L[Len//2+1:]))
a=[27,73,10,5,18,41,99,51,25]
B=f(sorted(a))

层序打印
(27) (18) (73) (10) (25) (51) (99) (5) (41)