Spreading Fire (Intuit India)

Spreading Fire (Intuit India) is a coding interview problem asked in Intuit interviews. You’re given an N×M 2D grid and K initial fire sources at integer coordinates. Fire spreads from each source in circles, with radius growing linearly over time (radius is R at t=1 and scales with T). For a given time T, determine how many grid points (integer (x, y) within the plane) remain untouched by any fire. Input includes N, M, K, the K coordinates, R, and T. This interview question focuses on geometric coverage and counting in a grid-based problem.