braces.py

braces.py

MATCHED_LOOKUP = {k: v for k, v in ["()", "[]", "{}"]}


def is_valid(string):
    open_braces = []

    for char in string:

        if char in MATCHED_LOOKUP:
            open_braces.append(char)

        else:
            if not open_braces or MATCHED_LOOKUP[open_braces.pop()] != char:
                return False

    return len(open_braces) == 0


for s in ["{}", "{[()]}({})", "{[}]", "{]}", "{[]}", "[]{", "{{}"]:
    print(s)
    print(is_valid(s))