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Age	Commit message (Collapse)	Author
2020-11-14	Trivial updates	Abigail

2020-11-14	Improve comment	Abigail

2020-11-14	Special case naked singles.	Abigail
	When we are solving, resolve naked singles without going into recursion. Naked singles are cells which have only one possibility left. For those cells, we cross off the possibility for all other unsolved cells in the same row, column or box, and put the cell in the set of solved cells. We keep resolving naked singles before recursing.
2020-11-14	Remove redundant parens	Abigail

2020-11-14	Fix comment	Abigail

2020-11-13	Fix comment	Abigail

2020-11-13	Remark we are using brute force	Abigail

2020-11-13	Solve X-sudokus.	Abigail
	If the option --X is given, we're assuming the Sudoku is an X-Sudoku. An X-Sudoku is a regular Sudoku with an additional constraint that the number on the main and anti-diagonals are unique. This was very easy to implement -- other than parsing the option, all that needed to be changed was the method which determines what other cells a particular cell can see.
2020-11-13	Remark we will use a module to do all the work	Abigail

2020-11-12	Some simplification.	Abigail
	Special handling of duplicate numbers only need to be taken if $diff equals 0. $n - $m == $A with $n == $m can only happen if $A == 0.
2020-11-11	Added lots of comments.	Abigail

2020-11-11	Improve readability.	Abigail

2020-11-11	Rename two variables	Abigail

2020-11-11	Use a bit field to keep track of possibilities.	Abigail

2020-11-11	Make an educated guess what the missing clue is.	Abigail
	It's possible to have NxN Sudoku's, with only different N-1 clues. If that is the case, we make an educated guess, based on whether the clues are numbers only, letters only, a mixture, and whether there are any "holes".
2020-11-11	Less restrictions on clues.	Abigail
	Some sudokus larger than 9x9 use all letters for clues. Some use numbers 1 .. 9 followed by letters. We're now excepting both. And we don't require them to be consecutive. It's possible to have one less different clue that the size of the sudoku, in that case, we have to make an educated guess (number or letter) what the missing clue is.
2020-11-11	Ignore lines not containing clues.	Abigail
	That is, any line which doesn't contain an underscore, digit or capital ASCII letter will be ignored. This makes inputting large sudoku's a tad bit easier, allowing blank lines or hyphens between blocks.
2020-11-11	Handle NxN sudokus where N is not a square.	Abigail
	Assumes a brick like pattern of blocks, where the blocks are wider than they are high.
2020-11-10	Pad output with spaces if $SIZE > 10, and the printed numbers are less.	Abigail

2020-11-10	Don't print '[ ' and ' ]' in the output.	Abigail

2020-11-10	Don't warn on deep recursion.	Abigail
	16x16 sudokus will reach the warn limit.
2020-11-10	Be more lenient in what the accept.	Abigail
	We know also accept letters 'A' .. 'Z' as clues. They will be mapped to 10 .. 35.
2020-11-10	Sudokus could be any size (assuming a square size)	Abigail

2020-11-10	Improve performance.	Abigail
	Instead of using a binary search to find matching numbers, we will be using a hash. This reduces the time complexity from O (N log N) worst case to O (N) expected.
2020-11-10	Perl solution for week 86, challenge 2.	Abigail

2020-11-09	Perl solution for week 86, part 1.	Abigail