I applied online and received an email from a recruiter with a link to a coding challenge.

I ended up not finishing the coding challenge in time and was rejected.

Grid Illumination: Given an N x N grid with an array of lamp coordinates. Each lamp provides illumination to every square on its x-axis, every square on its y-axis, and every square that lies on its diagonals (think of a Queen in chess). Given an array of query coordinates, determine whether that point is illuminated or not. The catch is: when checking a query, all lamps adjacent to, or on, that query get turned off. The ranges for the variables/arrays were about: 10^3 < N < 10^9, 10^3 < lamps < 10^9, 10^3 < queries < 10^9.