Z8-Rešenja
Table of Contents
Zadatak 1
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class Node:
def __init__(self, val):
self.val = val
self.left = None
self.right = None
def is_op(x):
return x in ['+', '-', '*', '/']
def is_num(x):
for i in range(len(x)):
if not x[i] in ('0123456789-' if i == 0 else '0123456789'):
return False
return True
def is_neg_num(x):
if x[0] == '-' and is_num(x):
return True
return False
def get_parse_three(s):
A = s.split(" ")[::-1]
(T, s) = get_parse_three_list(A)
return T
def get_parse_three_list(A):
if len(A) > 0:
if not is_op(A[0]):
n = Node(A[0])
return (n, A[1:])
else:
n = Node(A[0])
(n.right, A) = get_parse_three_list(A[1:])
(n.left, A) = get_parse_three_list(A)
return (n, A)
else:
return (None, '')
def eval_three(three, dictionary):
if not is_op(three.val):
if is_num(three.val):
return eval(three.val)
else:
return dictionary[three.val]
else:
if three.val == '+':
return (eval_three(three.left, dictionary) + eval_three(three.right, dictionary))
elif three.val == '-':
return (eval_three(three.left, dictionary) - eval_three(three.right, dictionary))
elif three.val == '*':
return (eval_three(three.left, dictionary) * eval_three(three.right, dictionary))
elif three.val == '/':
return (eval_three(three.left, dictionary) / eval_three(three.right,dictionary))
else:
print("SOMETHING WENT WRONG :(")
return None
def make_infix(three):
if not is_op(three.val):
if (is_neg_num(three.val)):
return "(" + three.val + ")"
else:
return three.val
else:
return "(" + make_infix(three.left) + " " + three.val + " " + make_infix(three.right) + ")"
if __name__ == "__main__":
test_cases = [("23 45 67 + -", None), ("a 5 + b c 3 / - *", {'a': 34, 'b': 65, 'c': 3}), ("vel_0 time * g time * time 2 / * +", {'vel_0': -10, 'time': 20, 'g': 9.81}), ("-3 -5 - 1 +", None)]
for test in test_cases:
(s, d) = test
T = get_parse_three(s)
print("INPUT STRING: \"", s, "\"", sep = "")
if d != None:
print("VARIABLE DICTIONARY:" , d)
print("EVAL_TREE RETURNS:", eval_three(T, d))
print("MAKE_INFIX RETURNS:", make_infix(T))
print()
zadatak1.py
