def isvalid(string):
validbrackets = {'(':')','[':']','{':'}'}
list1 =[]
for letter in string:
try:
closing = validbrackets[list1.pop()]
except:
return False;
if letter in validbrackets:
mystack.push (list1,letter)
elif (closing != letter):
return False
if(len(list1)==0):
return True;
def isvalid(string):
closeToOpen = {"}": "{", "]": "[", ")": "("}
closing = closeToOpen.keys()
opening = closeToOpen.values()
openStack = []
for i in string:
if i in opening:
mystack.push(openStack, i)
elif i in closing:
if not mystack.isempty(
openStack) and closeToOpen[i] == mystack.peek(openStack):
mystack.pop(openStack)
continue
return False
return mystack.isempty(openStack)
def test_length(self):
""" -- Verifica el numero de elementos de la lsita cuando son mayores a 1
"""
L = LinkedList()
push(L, "hola")
push(L, "jorge")
push(L, "como")
push(L, "va?")
res = length(L)
self.assertEqual(res, 4)
def isvalid(string):
closeToOpen = {"}": "{", "]": "[", ")": "(", "\"": "\"", "”": "“"}
closing = closeToOpen.keys()
opening = closeToOpen.values()
openStack = []
for i in string:
if i in opening:
#print ("Adding", i, openStack)
mystack.push(openStack, i)
elif i in closing:
if not mystack.isempty(
openStack) and closeToOpen[i] == mystack.peek(openStack):
#print ("Removing", closeToOpen[i], i, openStack)
mystack.pop(openStack)
continue
return False
#print (openStack)
return mystack.isempty(openStack)
def test_stack_ops(self):
""" -- Verifica que el ultimo elemento ingresado en la pila sea el primero en salir
"""
L = LinkedList()
push(L, "hola")
push(L, "jorge")
push(L, "como")
push(L, "va?")
first = pop(L)
second = pop(L)
self.assertEqual([first, second], ["va?", "como"])
import mystack
thestack = []
print("The stack should initially be: []")
print("Your stack is ", thestack)
print()
print("Trying to pop from an empty stack, should be None")
print(mystack.pop(thestack))
print()
print("Pushing 0 to stack, should be [0]")
mystack.push(thestack, 0)
print("Your stack is ", thestack)
print()
print("Pushing 1 to stack, should be [0, 1]")
mystack.push(thestack, 1)
print("Your stack is ", thestack)
print()
print("Pushing 2 to stack, should be [0, 1, 2]")
mystack.push(thestack, 2)
print("Your stack is ", thestack)
print()
print("Pushing 3 to stack, should be [0, 1, 2, 3]")
mystack.push(thestack, 3)
print("Your stack is ", thestack)
print()
print("Pop should return 3")
print(mystack.pop(thestack))
print()
print("Pop should return 2")
print(mystack.pop(thestack))
import mystack
stack = []
print ('Adding 5 to stack: ', mystack.push(stack, 5))
print ('Adding 6 to stack: ', mystack.push(stack, 6))
print ('Adding 7 to stack: ', mystack.push(stack, 7))
print ('Stack Empty: ', mystack.isempty(stack))
print ('Peeking at stack: ', mystack.peek(stack))
print ('Poping from stack: ', mystack.pop(stack))
print ('Printing stack: ', stack)
print ('Poping from stack: ', mystack.pop(stack))
print ('Printing stack: ', stack)
print ('Adding 8 to stack: ', mystack.push(stack, 8))
print ('Adding 9 to stack: ', mystack.push(stack, 9))
print ('Poping from stack: ', mystack.pop(stack))
print ('Printing stack: ', stack)
print ('Poping from stack: ', mystack.pop(stack))
print ('Printing stack: ', stack)
print ('Poping from stack: ', mystack.pop(stack))
print ('Printing stack: ', stack)
print ('Poping from stack: ', mystack.pop(stack))
print ('Printing stack: ', stack)
print ('Stack Empty: ', mystack.isempty(stack))
