012_valid_braces.py

# Write a function that takes a string of braces, and determines if the order of the braces is valid. It should
# return true if the string is valid, and false if it's invalid.
#
# This Kata is similar to the Valid Parentheses Kata, but introduces new characters: brackets [], and curly braces {
# }. Thanks to @earned for the idea!
#
# All input strings will be nonempty, and will only consist of parentheses, brackets and curly braces: ()[]{}.
# What is considered Valid?
#
# A string of braces is considered valid if all braces are matched with the correct brace.
# Examples

def checkbrackets(string):
    braces = {"(": ")", "[": "]", "{": "}"}
    stack = []
    for character in string:
        if character in braces.keys():
            stack.append(character)
        else:
            if len(stack) == 0 or braces[stack.pop()] != character:
                return False
    return len(stack) == 0



print(checkbrackets("()[]{}"))