Построение дерева цифрового поиска

f =open("f1.txt")
lines = f.read().split()
f.close()
 
def sort(array):
    equal =[]
    greater =[]
    less =[]
iflen(array)<=1:
returnarray
    linem =array[int((len(array)-1)/2)]
for line inarray:
if linem < line:
            greater.append(line)
elif linem > line:
            less.append(line)
elif linem == line:
            equal.append(line)
return sort(less) + equal + sort(greater)
 
sorted_lines = sort(lines)
print(sorted_lines)
 
def node(C, P):
print(P + C)
return P + " "
 
def R(P, K, I0, J0):
    I = I0
    Si = sorted_lines[I]
    Li =len(Si)
if K >= Li and I == J0:
return
if K < Li:
        C = Si[K]
else:
        C ="{0}"
    X = node(C, P)
    J = I
whileTrue:
if J == J0 or sorted_lines[J+1][K]!= C:
            R(X, K+1, I, J)
if J == J0:
break
            I = J + 1
            Si = sorted_lines[I]
            Li =len(Si)
            C = Si[K]
            X = node(C, P)
        J = J + 1
 
N =len(sorted_lines)
X = node("[ROOT_NODE]","")
R(X,0,0, N-1)

BC
ABBA
ABC
ABA
ABB
BAC
A

['A', 'ABA', 'ABB', 'ABBA', 'ABC', 'BAC', 'BC']
[ROOT_NODE]
 A
  {0}
  B
   A
   B
    {0}
    A
   C
 B
  A
   C
  C