BITSCTF 2025: Minesweeper 2

Minesweeper has a wierd name don’t you think you don’t actually sweep any mines in it so I decided to make it better.

nc chals.bitskrieg.in 7006

dipper

README.md

A $m\times n$ board yields a system of linear equations in $mn$ variables. Each variable $a_{ij}$ represents the number of mines at row $i$, column $j$. Each equation sets a constraint on how many mines can be at a location’s neighbors based on the number in its tile. For example, if there are $b_{23}$ mines adjacent to a non-edge tile at row $2$, column $3$, the correpsonding equation is $a_{13} + a_{22} + a_{33} + a_{24} = b_{23}$.

Normally, such systems are solved using Gaussian elimination in $O((mn)^3)$. Luckily, our system of equations is very sparse, so scipy.sparse can solve the system more quickly.

Flag: BITSCTF{D0_u_y34rn_f0R_th3_m1n3s?}

The final solve script can be found here.