reiwaCTF_zeroha_solve.py

import socket
from sympy import *  # noqa

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(('zerois-o-reiwa.seccon.jp', 23615))
x = symbols('x')

while True:
    number = s.recv(2048)
    print('number is', number)
    formula = s.recv(2048).decode('utf-8')
    formula = formula.replace('?', 'x')
    formula = formula[2:-2]
    print(formula)
    send = str(solve(formula, x))[1:-1] + '\n'
    if send == '\n':
        send = '0\n'
    print(send)
    s.sendall(str(send).encode('utf-8'))