The morale of today's lecture

Before designing an algorithm: find a good visual representation for the input and output helps you think about the problem.

Case in point: Viterbi's algorithm. Input includes so much data that it's messy to think about, until the right graph is drawn (with colors, too.)

For when the input is a permutation: represent it as a collection of points (i,sigma(i)), and hope that the output of the problem can be interpreted visually.