def infix_to_postfix(self):
"""
Prevod infixniho vyrazu na postfixni
"""
data = self.get_data()
infix_arr = []
postfix_arr = []
val = ""
for item in data:
if self.is_operation(item):
if val != "":
infix_arr.append(float(val))
infix_arr.append(item)
val = ""
elif item == "(":
infix_arr.append(item)
elif item == ")":
if val != "":
infix_arr.append(float(val))
infix_arr.append(item)
val = ""
else:
val += item
if val != "":
infix_arr.append(float(val))
stack = Stack()
for item in infix_arr:
if self.is_operation(item):
if self.get_operation_pritorty(
item) < self.get_operation_pritorty(stack.first()):
for op in stack.to_list():
if op == "(":
continue
postfix_arr.append(op)
stack.clear()
stack.push(item)
elif item == "(":
stack.push(item)
elif item == ")":
while stack.first() != "(":
op = stack.pop()
postfix_arr.append(op)
else:
postfix_arr.append(item)
for op in stack.to_list():
if op == "(":
continue
postfix_arr.append(op)
return " ".join(map(str, postfix_arr))
class Queue(object):
"""
Queue is an abstract data structure, somewhat similar to
Stacks. Unlike stacks, a queue is open at both its ends.
One end is always used to insert data (enqueue) and the
other is used to remove data (dequeue)
"""
def __init__(self):
self.stack1 = Stack()
self.stack2 = Stack()
def enQueue(self, item):
self.stack1.push(item)
def deQueue(self):
if len(self.stack2) == 0:
if len(self.stack1) == 0:
return None
while self.stack1.isEmpty() != True:
self.stack2.push(self.stack1.pop())
return self.stack2.pop()
def peek(self):
if len(self.stack2) == 0:
return self.stack1.first()
else:
return self.stack2.peek()
