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First solution in Clear category for Brackets by repoi
def checkio(expression):
# reduce to brackets only
expression = "".join( c for c in expression if c in "{}()[]" )
# don't bother if expression is unbalanced
if len(expression)%2 != 0:
return False
# iteratively remove inner brackets until there are no more
while expression:
len_before = len(expression)
expression = expression.replace("()","")
expression = expression.replace("{}","")
expression = expression.replace("[]","")
if len(expression) == len_before: # if no change, then its False
return False
# if we removed all the brackets, then its True
return True
#These "asserts" using only for self-checking and not necessary for auto-testing
if __name__ == '__main__':
assert checkio("((5+3)*2+1)") == True, "Simple"
assert checkio("{[(3+1)+2]+}") == True, "Different types"
assert checkio("(3+{1-1)}") == False, ") is alone inside {}"
assert checkio("[1+1]+(2*2)-{3/3}") == True, "Different operators"
assert checkio("(({[(((1)-2)+3)-3]/3}-3)") == False, "One is redundant"
assert checkio("2+3") == True, "No brackets, no problem"
April 9, 2016
