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First solution in Clear category for Brackets by joseke
def checkio(expression):
brackets,bh={"{":"}","(":")","[":"]"},[""]#bh stands for bracket history
for item in expression:
if item in brackets.keys()or item in brackets.values():
if bh[-1] in brackets.keys() and item in brackets.values():
if brackets[bh[-1]]!=item:
return False
else:
del bh[-1]
else:
bh.append(item)
if len(bh)==1:
return True
else:
return False
#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"
July 25, 2020
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