How Good Are You At Guess Who?

The most recent Riddler Express gave me an opportunity to refresh some base R notation, as well as combine it with a technique I learned while reading Hadley Wickham’s Advanced R. The challenge is: A local cafe has board games on a shelf, designed to keep kids (and some adults) entertained while they wait on their food. One of the games is a tic-tac-toe board, which comes with nine pieces that you and your opponent can place: five Xs and four Os.

in r

March 8, 2020

How Many More Palindrome Dates Will You See?

I’m currently on paternity leave and in search of quick but interesting programming challenges to stay fresh. The latest Riddler Express provided a quick refresher on string manipulation. If we write out dates in the American format of MM/DD/YYYY (i.e., the two digits of the month, followed by the two digits of the day, followed by the four digits of the year), how many more palindromic dates will there be this century?

in r

February 8, 2020

Winning the World Chess Championship

This week’s Riddler Express from FiveThirtyEight: The World Chess Championship is underway. It is a 12-game match between the world’s top two grandmasters. Many chess fans feel that 12 games is far too short for a biennial world championship match, allowing too much variance. Say one of the players is better than his opponent to the degree that he wins 20 percent of all games, loses 15 percent of games and that 65 percent of games are drawn.

in r

November 16, 2018

Cubs World Series Puzzles (For Fun)

This week’s Riddler Express from FiveThirtyEight: The best team in baseball this year, the Chicago Cubs, have clinched their playoff spot and will play their first playoff game a week from today. The Cubs’ road to the World Series title consists of a best-of-five series followed by two best-of-seven series. How many unique strings of wins and losses could the Cubs assemble if they make their way through the playoffs and win their first championship title since 1908?

in r

October 6, 2016

A Modified Draft Pick Selection Order

In preparation for teaching a new computing course for the social sciences, I’ve been practicing building interactive websites using Shiny for R. The latest Riddler puzzle from FiveThirtyEight was an especially interesting challenge, combining aspects of computational simulation and Shiny programing: You are one of 30 team owners in a professional sports league. In the past, your league set the order for its annual draft using the teams’ records from the previous season — the team with the worst record got the first draft pick, the team with the second-worst record got the next pick, and so on.