Finding all combinations of well-formed brackets

Question

This came up while talking to a friend and I thought I\'d ask here since it\'s an interesting problem and would like to see other people\'s solutions.

The task is to

Answer 1

def form_brackets(n: int) -> set:
    combinations = set()
    if n == 1:
        combinations.add('()')
    else:
        previous_sets = form_brackets(n - 1)
        for previous_set in previous_sets:
            for i, c in enumerate(previous_set):
                temp_string = "{}(){}".format(previous_set[:i+1], previous_set[i+1:])
                combinations.add(temp_string)

    return combinations