tldr;- the task is to break a truncated LCG given some LSB and some MSB- the LCG uses an unknown increment- this paper https://www.math.cmu.edu/~af1p/Texfiles/RECONTRUNC.pdf gives an overview on how to break the LCG- LLL -> win- read the writeup for actual details
[DUCTF GitHub](https://github.com/DownUnderCTF/Challenges_2020_public/tree/master/crypto/lsb-msb-calculation-game)
[writeup](https://jsur.in/posts/2020-09-20-downunderctf-2020-writeups#lsb-msb-calculation-game)