ELI5: Explain Like I'm 5

Reverse computation

Reverse computation is a way to do operations or calculations in reverse order from how you normally would. Instead of starting with some inputs and figuring out what the output will be, you start with the output and try to figure out what inputs could have given you that result.

Imagine you're playing a game where you have to guess a number. You get to make guesses and the game tells you whether your guess is too high or too low. When you finally guess the right number, the game tells you how many guesses it took. Reverse computation in this situation would be like asking "If it took me six guesses to get the right number, what were all of the guesses I made?"

In math, reverse computation is sometimes called "backwards induction" and it's commonly used in problems involving probability or game theory. For example, if you're trying to figure out the optimal strategy for a game of poker, you might start by figuring out what your opponents could do in response to different moves you make, and then work backwards to determine what move you should make in each scenario.

Overall, reverse computation is a useful tool for problem-solving and decision-making, especially in situations where the outcome depends on multiple factors and it's not immediately obvious what the best course of action is.