def parenthesesChecker(string):
"""
Parentheses Checker validates the string using stack
INPUT
---------
string : '(()))'
RETURN
---------
Flag : False
"""
temp = Stack(); balanceFlag = False
for i in string:
if i == "(":
temp.push('i')
if i == ")":
if temp.isEmpty():
balanceFlag = False
else:
temp.pop();
balanceFlag = True
if balanceFlag and temp.isEmpty():
return True
else:
return False
def test_isEmpty(self):
stack_empty = Stack()
stack_full = Stack()
stack_full.push('test')
self.assertEqual(stack_empty.isEmpty(), True)
self.assertEquals(stack_full.isEmpty(), False)
def toStr(n, base):
"""
Convert given number to number in different base
Instead of concatenating the result of the recursive call to toStr with the string
from stringMap, Push the strings onto a stack instead of making the recursive call
INPUT
-------
n : Input number eg 1453
base : base to convert the number to eg. 16 or Hexadecimal
RETURN
-------
newStr = (1453,16) => 5AD
"""
tempStack = Stack()
stringMap = '0123456789ABCDEF'
newStr = ''
while (n > 0):
quotient = n // base
remainder = n % base
if remainder > 9:
tempStack.push(stringMap[remainder])
else:
tempStack.push(remainder)
n = n // base
while not tempStack.isEmpty():
newStr += str(tempStack.pop())
return newStr
def rev_string(test_str): string_stack = Stack() for ch in test_str: string_stack.push(ch) reverse_string = '' while not string_stack.isEmpty(): reverse_string = reverse_string + string_stack.pop() return reverse_string
def rev_string(test_str):
string_stack = Stack()
for ch in test_str:
string_stack.push(ch)
reverse_string = ''
while not string_stack.isEmpty():
reverse_string = reverse_string + string_stack.pop()
return reverse_string
def testStack(self):
stack = Stack()
self.assertTrue(stack.isEmpty())
stack.push(5)
self.assertFalse(stack.isEmpty())
stack.clear()
self.assertTrue(stack.isEmpty())
stack.push(6)
self.assertEqual(6, stack.top())
self.assertEqual(6, stack.pop())
self.assertTrue(stack.isEmpty())
stack.push(7)
stack.push(6)
stack.push(5)
self.assertEqual(5, stack.pop())
self.assertEqual(6, stack.pop())
self.assertEqual(7, stack.top())
def testStack(self):
stack = Stack()
self.assertTrue(stack.isEmpty())
stack.push(5)
self.assertFalse(stack.isEmpty())
stack.clear()
self.assertTrue(stack.isEmpty())
stack.push(6)
self.assertEqual(6, stack.top())
self.assertEqual(6, stack.pop())
self.assertTrue(stack.isEmpty())
stack.push(7)
stack.push(6)
stack.push(5)
self.assertEqual(5, stack.pop())
self.assertEqual(6, stack.pop())
self.assertEqual(7, stack.top())
def divide_by_2(dec_num): remstack = Stack() while dec_num > 0: rem = dec_num % 2 remstack.push(rem) dec_num = dec_num // 2 bin_string = "" while not remstack.isEmpty(): bin_string = bin_string + str(remstack.pop()) return bin_string
def divide_by_2(dec_num):
remstack = Stack()
while dec_num > 0:
rem = dec_num % 2
remstack.push(rem)
dec_num = dec_num // 2
bin_string = ""
while not remstack.isEmpty():
bin_string = bin_string + str(remstack.pop())
return bin_string
def isBallanced(str):
open = '(', '[', '{'
close = ')', ']', '}'
st = Stack()
for ch in str:
if ch in open:
st.push(ch)
elif ch in close:
if st.isEmpty():
return False
idxClose = close.index(ch)
op = st.pop()
idxOpen = open.index(op)
if idxClose != idxOpen:
return False
if not st.isEmpty():
return False
return True
