The firefighter problem defines a discrete-time process where a fire starts at a designated subset of the vertices of a graph G. At each subsequent discrete time unit, the fire propagates from each burnt vertex to all of its neighbors unless they are defended by a firefighter. Once a vertex is burnt or defended, it remains in that state, and the process terminates when the fire can no longer spread.
The Spreading method says that the vaccination can spread from the nodes to their neighbors just like infection/fire
The Non-Spreading method says that the vaccination cannot spread from the nodes to their neighbors just like infection/fire, meaning that the vaccination is static
In the MaxSave algorithm, giving a certain budget, we need to save as many nodes that we can from the targeted nodes
In the MinBudget algorithm, we need to find the minimal budget that will save all the targeted nodes