How does SARSA handle episode termination

Question

When applied to domains that are episodic and have a "final" state but no final action, like a game, how does SARSA update the Q-values?

e.g. A game agent would receive this series: $$ s_0,a_0,r_0,s_1,a_1,r_1,.....s_{N-1},a_{N-1},r_{N-1},s_N $$ Based on the traditional definition, which updates the current Q-value using the *future Q-value, shouldn't it be impossible to apply SARSA, since there's no future action to use when plugging in the $(s_t, a_t, r_t, s_{t+1}, a_{t+1})$ values?

Answer 1

You can think of the terminal state as a loop for every possible action where you receive zero reward. Once you enter the terminal state, not matter what action you choose, you will receive zero reward.