script me

https://gyazo.com/28cfe5bf6b048f41614630019a2c915f

Problem:

Hint:

Maybe try writing a python script?

code:sh

Rules:

Example:

(()) + () = () + (()) = (()())

Let's start with a warmup.

() + (()()) = ???

解読のために人に読みやすい形に変換する

三十二ではなく、3と2

code:main.py

def decode(s):

s = s.replace('()', '1')

for i in range(1, 10):

if ('(' + str(i) + ')') not in s:

break

s = s.replace('(' + str(i) + ')', str(i+1))

return s

def encode(s):

for i in range(1, 10):

s = s.replace(str(i), ('(' * i) + (')' * i))

return s

Aは3、Bは2、Cは1のネストにいるので、それぞれに加算していく

数字が大きい方が小さい方を吸収する

code:compare.py

def compare(left, right):

if left == right:

return 'same'

l_power = calc_power(left)

r_power = calc_power(right)

if l_power > r_power:

return 'left'

if l_power < r_power:

return 'right'

return 'same'

def calc_power(statement):

count = 0

power = 0

for c in statement:

if c == '(':

count = count + 1

elif c == ')':

count = count - 1

else:

power = max(power, int(c) + count)

return power

長過ぎる標準出力を受け取るのにめっちゃ手こずった...

https://gyazo.com/0a975ccc368cd37501318e6750425241

出題が長すぎて、問題が2回に分けられて送られてきていた

気づかないままずっと施行していたら、最後の問題だけ解けないという場面に遭遇してしまった

最終的には結構ゴリ押した

Exampleの行がごまかすのが面倒だった

code:script_me.py

from netcat import Netcat

from compare import compare

def decode(s):

s = s.replace('()', '1')

for i in range(1, 10):

if ('(' + str(i) + ')') not in s:

break

s = s.replace('(' + str(i) + ')', str(i+1))

return s

def encode(s):

for i in range(1, 10):

s = s.replace(str(i), ('(' * i) + (')' * i))

return s

def main():

nc = Netcat('2018shell2.picoctf.com', 8672)

code = ''

for i in range(15):

lines = nc.read().decode('utf-8').split('\n')

statement = []

for line in lines:

if ('Expected => ' in line):

print('\nExpected => ' + decode(line.lstrip('Expected => ').replace(' ', '').replace('\n', '')))

continue

if ('Actual => ' in line):

print('Actual => ' + decode(line.lstrip('Actual => ').replace(' ', '').replace('\n', '')))

continue

if (' => ' not in line) and ('(' in line) and (')' in line) and ('(()) + () = () + (()) = (()())' not in line):

print(line + '\n')

code = code + line

continue

print(line)

if ' = ???' not in code:

continue

code = code.rstrip(' = ???')

statement = decode(code).split(' + ')

code = ''

if len(statement) == 1:

continue

left_stack = ''

while len(statement) != 1:

left = statement.pop(0)

stronger = compare(left, right)

left = encode(left)

right = encode(right)

calculated = ''

if stronger == 'same':

calculated = right

left_stack = left_stack + left

elif stronger == 'left':

elif stronger == 'right':

left_stack = ''

nc.close()

if __name__ == '__main__':

main()

$ python3 script_me.py