```python
def undo_thing(a, b):
return (a ^ b) >> 1

x = 'a' * 25

random.seed(997)
k = [random.randint(0, 256) for _ in range(len(x))]
print("k =", k)
a = { b: do_thing(ord(c), d) for (b, c), d in zip(enumerate(x), k) }
b = list(range(len(x)))
random.shuffle(b)
c = [a[i] for i in b[::-1]]
kn = [47, 123, 113, 232, 118, 98, 183, 183, 77, 64, 218, 223, 232, 82, 16, 72, 68, 191, 54, 116, 38, 151, 174, 234, 127]
valid = len(list(filter(lambda s: kn[s[0]] == s[1], enumerate(c)))) # i.e. c = kn

print("---")

c = kn
print("Need c =", c)
a = [None for _ in range(len(b[::-1]))]
for i in range(len(b[::-1])):
a[b[::-1][i]] = c[i]
print("Need a =", a)

undo_a = { b: chr(undo_thing(a[b], d)) for (b, c), d in zip(enumerate(x), k) }
print(''.join(undo_a[i] for i in range(25)))
```

[Read the Full Writeup Here](https://ctf.zeyu2001.com/2021/metactf-cybergames/i-hate-python)

Original writeup (https://ctf.zeyu2001.com/2021/metactf-cybergames/i-hate-python).