Before revision:  Since it is an NP-hard problem, many approximate/heuristic methods have been developed, and a number of them repeats Monte Carlo (MC) simulations over and over , specifically tens of thousands of times or more per potential seed set, to reliably estimate the influence .
After revision:  Since it is an NP-hard problem, many approximate/heuristic methods have been developed, and a number of them repeats Monte Carlo (MC) simulations over and over to reliably estimate the influence .