Valid parentheses
class Solution:
def isValid (self, sequence: str):
'''
Function to pair if sequence contains valid parenthesis
:param sequence: Sequence of brackets
:return: True is sequence is valid else False
'''
stack = []
opening = set('([{')
closing = set(')]}')
pair = {')' : '(' , ']' : '[' , '}' : '{'}
for i in sequence :
if i in opening :
stack.append(i)
if i in closing :
if not stack :
return False
elif stack.pop() != pair[i] :
return False
else :
continue
if not stack :
return True
else :
return False
if __name__ == '__main__':
sequence = '{[()]}'
print(f'Is {sequence} valid ? : {Solution().isValid(sequence)}')
sequence1 = '{[()]}{]{}}'
print(f'Is {sequence1} valid ? : {Solution().isValid (sequence1)}')