A few weeks ago I was introduced to Futoshiki, a Japanese puzzle. It was in the Gulf News, which I was reading in the U.A.E. while there on a business trip.
Once I got back home, I was wondering if I could write a program to do this by Integer Programming (IP). The technique is similar to solving Sudoku puzzles via IP.
I wrote a description of the formulation and uploaded it as a PDF file, I hope you find this interesting. To solve the puzzle I used the Gurobi solver, coding in Python. The problem size, with a 5×5 puzzle, is small enough to solve with the trial edition of Gurobi. In future posts I’ll find new ways to abuse math programming systems for games and other diversions 🙂
https://mathstream.com/wp-content/uploads/2012/08/futoshiki.pdf
