Recursion

Data that contains smaller copies of itself, nested as deep as it likes: folders, menus, replies to replies. Every one of these is solved by a function that calls itself on a smaller piece and knows when to stop, and every one has a way to get the stopping wrong.

9 exercisesdifficulty 2–4~200 min in total

—Exercises 9 exercises

Flatten a list of lists of lists recursion, base case ~20 min Add up numbers hidden at any depth recursion, base case ~15 min How deep does it go? recursion, max of the answers ~15 min Every way to choose from a list recursion that branches, building new lists ~25 min Every order the letters can go in permutations, recursion that branches ~25 min Find it in a sorted list by halving binary search, recursion on a range ~25 min How much space is this folder using? recursion over a tree, two kinds of node ~20 min Move the tower, one disc at a time recursion with two calls, trusting the smaller call ~25 min Sort a list by splitting it in half divide and conquer, merging two sorted lists ~30 min