Dynamic Programming

When solving this problem, we must first observe how word1 becomes word2. Taking Example1 as an example, the lower left figure lists the distance from “horse” to “ros”.

In this problem, wordA is a predecessor of wordB which means we only need to insert a letter in wordA to make it the same as wordB.

What this problem needs to solve is to calculate the minimum possible height of the bookshelf after placing all the books into the bookshelf.

This problem asks us to calculate the total number of all possible paths from the top-left corner to the bottom-right corner. We can observe that to go from the top-left corner to the bottom-right corner, the robot can only go right or down.