Memoize with a struct in Rust
Rust interview exercise on Closures & Iterators, difficulty 3 of 3. Solve it in the editor beside a worked example, or cold in Interview mode with the example hidden; the tests run the moment you do.
Implement Cacher: new(f) stores the closure, and get(n) returns f(n), calling f only the first time each n is asked for and answering from the HashMap afterwards.
Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Interview mode hides the example: solve it from memory, without the hint or the solution, and it counts as solved cold. Progress is saved in your browser, and in your account if you sign in.