# English Sucks
## __Description__
English is such a confusing language. Can you help me understand it?
nc misc.hsctf.com 9988
[mt.cpp](mt.cpp)
## __solution__
The given code generate 216 strings each with 3 random integers by [mt19937](https://en.wikipedia.org/wiki/Mersenne_Twister) which is an pseudorandom number generator.
```std::mt19937 random{std::random_device()()};
auto v1 = random();auto v2 = random();auto v3 = random();```
According to [this](https://github.com/kmyk/mersenne-twister-predictor), you can predict MT19937 from preceding 624 generated numbers.
But take a look the code it generate strings
```std::cout << "BCDGPTVZ"[v2 >> 0x1F & 0x1 | v3 >> 0x0 & 0x3]          << "BCDGPTVZ"[v1 >> 0x09 & 0x7]          << "BCDGPTVZ"[v3 >> 0x05 & 0x7]          << "BCDGPTVZ"[v3 >> 0x08 & 0x7]...```
It take every 3 bits of the numbers and decide a character.
However, the first and the last bits are not confirmable because the OR operation. That causes the uncertainty of the answer.
Write a [script](solve.py) with the predictor and try it several times until it success.
![alt text](solve.png)
```hsctf{y0u_kn0w_1_h4d_t0_d0_1t_t0_3m_rng_god}```