Parsing Code Results

The code snippet provided appears to demonstrate the usage of a `Memo` class and its `GetReduceGroupId` method, which takes a `GroupId` as input and returns an `optional` `ReducedGroupId`. The code prints the results of calling this method with different values. However, the results of the three method calls are identical, which may seem puzzling at first glance.

The reason for this is due to the usage of the `std::cout` statement inside the `GetReduceGroupId` method, which prints the value of the `reduced_group_id` variable. This causes the compiler to optimize away the `std::optional` wrapper, returning the value directly.

In order to avoid this optimization, the `std::optional` wrapper can be removed by using a different method to return the value. For example, the method could return a `ReducedGroupId` directly:

struct Memo {
ReducedGroupId GetReduceGroupId(const GroupId& group_id) {
// omit
return group_id;
}
};

This would allow the code to produce the expected output, with different results for the three method calls.