Programming, problem solving, and algorithms

CPSC 203, 2025 W1

November 4, 2025

Announcements

The only thing that we could have a little more of the same kind words and the answers are very very important

Following Ada

Supposing, for instance, that the fundamental relations of pitched sounds in the science of harmony and of musical composition were susceptible of such expression and adaptations,

the engine might compose elaborate and scientific pieces of music of any degree of complexity or extent.

(Ada Lovelace – 1842)

Prelude

Characterizing Mary

Building a Music Generator

Building a Song

Building a Song

Demo

PrairieLearn Activity

Some Technical Details

• You have just learned about a particular type of random process called a Markov Chain.

• We modelled it using a transition table, or a finite state machine, and we used it as the basis for an algorithm to generate music.

Graphs?

This table can be interpreted as an adjacency matrix representation of a graph.

 

Vertices:

 

Edges:

 

Special characteristics:

http://setosa.io/markov

The only thing that we could have a little more of the same kind words and the answers are very very important

Other Applications

• PageRank: Google’s first search algorithm
  • Some pages are likely to “follow” (be linked from) others.
  • Rank of page is based on the probability that you’ll be there at any moment
• Natural Language Processing
  • Some words are more likely to follow others.
  • “I just ate the whole desert” probably has a misspelling.
  • “For dinner I ___ …” next word is probably “ate”
• DNA matching
• Chemical reaction simulation

Many others…