6 lines solution clear solution for Remove Brackets by kdim - python coding challenges

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6 lines solution solution in Clear category for Remove Brackets by kdim

from re import search, sub
def remove_brackets(line: str) -> str:
    p, l = r'\(\)|\[\]|\{\}', len(line)
    check = lambda x: check(sub(p, '', x)) if bool(search(p, x)) else x
    subst = lambda x: ''.join(a * int(b) for a, b in zip(line, f'{x:0{l}b}'))
    return max((subst(i) for i in range(2 ** l) if not check(subst(i))), key=len)

Feb. 4, 2021

Comments:

Sebdidier on Feb. 12, 2021, 6:22 p.m.
Nice solution, good use of lambdas and regex!

jakubbortlik on Nov. 21, 2022, 1:25 p.m.
Well, I guess this belongs to the creative category. The use of recursion, binary, deleting characters by multiplying by 0, etc. make it quite hard to grasp. But I will definitely try to, because it just seems to teach a number of interesting things. I've rewritten the solution to use normal function instead of lambdas, so that I could go through it step by step in a debugger, so here it is in case anybody else would find it useful: ``` from re import search, sub def check(x): pattern = r"()|[]|{}" return check(sub(pattern, "", x)) if bool(search(pattern, x)) else x def subst(x, line): length = len(line) return "".join(a * int(b) for a, b in zip(line, f"{x:0{length}b}")) def remove_brackets(line: str) -> str: return max( (x for i in range(2 ** len(line)) if not check(x := subst(i, line))), key=len ) ```

jakubbortlik on Nov. 22, 2022, 8:48 a.m.
Last notes: I find the code easier to understand if the `check` function returns `True` for correct brackets and `False` for incorrect brackets, so I'd suggest to move the `not` from the return statement to the first lambda: ``` check = lambda x: check(sub(p, '', x)) if bool(search(p, x)) else not x ``` ``` return max((s for i in range(2 ** l) if check(s := subst(i))), key=len) ```

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