solvingsudoku-universityofnottingham(編輯修改稿)
2025-06-16 22:41 本頁面
【文章內(nèi)容簡介】 d is essentially a list of lists, but matrices and rows will be useful later on. 13 Examples easy :: Grid easy = [ 2 1 38 , 5 , 7 6 , 13 , 981 257 , 31 8 , 9 8 2 , 5 69784 , 4 25 ] empty :: Grid empty = replicate 9 (replicate 9 39。 39。) 14 Extracting Rows rows :: Matrix a ? [Row a] rows m = m 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 15 … Columns cols :: Matrix a ? [Row a] cols m = transpose m 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 5 9 13 2 6 10 14 3 7 11 15 4 8 12 16 16 … And Boxes boxs :: Matrix a ? [Row a] boxs m = omitted 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 2 5 6 3 4 7 8 9 10 13 14 11 12 15 16 17 Validity Checking Let us say that a grid is valid if it has no duplicate entries in any row, column or box: valid :: Grid ? Bool valid g = all nodups (rows g) ? all nodups (cols g) ? all nodups (boxs g) A direct implementation, without concern for efficiency. 18 Making Choices Replace each blank square in a grid by all possible numbers 1 to 9 for that square: choices :: Grid ? Matrix [Char] 1 2 3 4 5 6 3 7 8 9 1 2 3 4 4 5 6 7 8 9 3 4 19 Collapsing Choices Transform a matrix of lists into a list of matrices by considering all binations of choices: collapse :: Matrix [a] ? [Matrix a] 1 3 4 1 2 3 4 2 2 3 4 1 1 3 4 2 1 2 3 4 1 2 20 A Brute Force So
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