Oh Shakti, you spoilsport!!Originally Posted by Shakti
Manav, I don't know your experience, but I wrote a Sudoku solver last year, and it was quite tricky. Perhaps because I had not played Sudoku before I started the program, and am a hobby programmer, not a pro.
In any case, the code is LONG*, and the algorithm is tricky, e.g. it repeatedly uses a 2D to 1D array manipulation - very unexpected.
My thought is that if you had the code, you wouldn't understand it, unless you had enough skill to code it yourself. If you had that skill, you wouldn't need the code.
Beyond the obvious solitary "must be this number, here", and "can't include this possibility on this square over here", you need to read up on "the rule of pairs" (either inside, or outside, or both), and how to switch to guessing for the toughest Sudoku puzzles, when all other techniques are exhausted, and the puzzle is still unsolved.
*my solver uses a fast technique, or a very slow "odometer" technique. The latter is a tribute to a friend who died most unexpectedly. (An odometer was the first bit of code he asked me to write for him.)
You'll like this challenge of writing a Sudoku program, Manav. You don't want to underestimate it.
