#Given expression containing parenthesis output an expression that contains balenced parenthesis

#example:

#")(" -> ""

#"((())" -> "(())"

#"()())()" -> "()()()" or "(())()"

class Approch1(object):

def __init__(self, string):

self.string = string

def replace(self, string, index):

return string[:index]+"0"+string[index+1:]

def check(self):

stack = []

for i in range(len(self.string)):

if(self.string[i] == "("):

stack.append(i)

else:

if(stack and self.string[stack[-1]] == "("):

stack.pop()

else:

stack.append(i)

for i in stack:

self.string = self.replace(self.string, i)

output = ""

for letter in self.string:

if letter == "(" or letter == ")":

output = output+letter

print output

#Main

o = Approch1(")(")

o.check()

o = Approch1("(()))")

o.check()