idekCTF 2022* -- Manager Of The Year 1

idek2022_manager1_solve.py

from pwn import *

r = remote('manager-of-the-year-1.chal.idek.team', 1337)
r.sendlineafter(b'Press any key to continue...', b'')

rmse = []

# send 365 zero
r.sendlineafter(b'Enter your predictions for \'Revenue\' (in thousands) for 2023:\n', 
                ' '.join(['0']*365).encode())
res = r.recvline().decode()
rmse.append(float(res.split('(')[1].split(')')[0]))

# send 364 zero and 1 "100"
# example0: 100 0 0 0...
# example1: 0 100 0 0...
for i in range(365):
    to_send = ['0']*365
    to_send[i] = '100'
    r.sendlineafter(b'Enter your predictions for \'Revenue\' (in thousands) for 2023:\n', 
                    ' '.join(to_send).encode())
    res = r.recvline().decode()
    rmse.append(float(res.split('(')[1].split(')')[0]))

# calculate the correct value by using the RMSE formula
n = len(rmse) - 1 # 365
correct_value = []
for i in range(365):
    correct_value.append(str(round(((rmse[i+1]**2 - rmse[0]**2) * n - 100**2) / -200, 2)))
r.recvuntil(b'Enter your predictions for \'Revenue\' (in thousands) for 2023:\n')
r.sendline(' '.join(correct_value).encode())

r.interactive()