A Common-Sense Guide to Data Structures and Algorithms in Python, Volume 1

Chapter 11

These are the solutions to the exercises found in the section ​Exercises​.

1. Let’s call our function character_count. The first step is to pretend that the character_count function has already been implemented.

   Next, we need to identify the subproblem. If our problem is the array ["ab", "c", "def", "ghij"], then our subproblem can be the same array missing one string. Let’s specifically say that our subproblem is the array minus the first string, which would be ["c", "def", "ghij"].

   Now, let’s see what happens when we apply the “already-implemented” function on the subproblem. If we were to call character_count(["c", "def", "ghij"]), we’d get a return value of 8, since there are eight characters in total.

   So to solve our original problem, ...