Rating:

# A Happy Family (74 solves)

> Clam became a parent and had a child. Or at least he dreamed about it. Anyway, clam wrote a program to describe his dream. In fact, he's so happy that he provided source!
>
> Find it on the shell server at /problems/2020/a_happy_family.
>
> The sha256 hash (no newline) of the correct input is aa15a7b191ffa943fa602f7472ef294c6b5d138a629ac2bb75cb6ac57bfc3257.
>
> Author: aplet123

Solution:

First, find all possible n1, n2, n3, n4 (check **find_all_possible** function)

Next, apply reverse math on them and convert back to string.

Copy those strings that have all printable characters in them.

In the end, we have 1 in n1, n2, n3 and 4 in n4

`python
from itertools import zip_longest, product
import sys
from struct import *
import string

alphabet = "angstromctf20"
alphabet_st = "0123456789ABC"

flags = {
'c1' : 'artomtf2srn00tgm2f',
'c2' : 'ng0fa0mat0tmmmra0c',
'c3' : 'ngnrmcornttnsmgcgr',
'c4' : 'a0fn2rfa00tcgctaot'
}

def find_all_possible(inp):
th_nums = [[alphabet_st[i] for i, y in enumerate(alphabet) if y == x] for x in inp]
variants = [''.join(x) for x in product(*th_nums) ]
nums = [int(x, 13) for x in variants]
return nums

def main():
n1 = pack('