Sunday, May 4, 2008

Pi Sudoku

The challenge is (was) to fit in as many digits of pi as possible in a sudoku grid. The first 0 that appears in pi's decimal expansion is in the 33rd digit (pi = 3. 1415926535 8979323846 2643383279 5028841971 ...), so we are trying to fit the first 32 digits in a 9x9 grid so that we will have a regular sudoku puzzle with a unique solution. You start with 3 at any square, then proceed to put 1 in a neighboring square (horizontal, vertical or diagonal), and so on. You cannot pass through a square once you used that square.

The task didn't prove too difficult. I used an online sudoku solver for help, and it seems 32 digits is not too many to fit in the grid. The solution I got:



Another challenge here could be only allowing horizontal and vertical steps.