Memoize a function in C#
C# interview exercise on Delegates & 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.
Write Memoize(fn) that returns a function with the same results as fn, which calls fn only the first time each argument is seen and answers from a Dictionary 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.