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Interesting exposition about how to use Exact Cover to solve a Sudoku. But in case a sudoku has one solution, it is possible to solve it by reducing the exact c
by fjfaase 4y ago
Interesting exposition about how to use Exact Cover to solve a Sudoku. But in case a sudoku has one solution, it is possible to solve it by reducing the exact cover. For example, if you have a column that is a true subset of another column (with respect to the 1-s) you can remove all the rows that have a 1 in the row with the larger number, because these rows can never be selected.
Also when solving an Exact Cover there are some (rather simple) strategies that can improve the speed of finding solutions.
I used Exact Covers a lot for solving all kinds of puzzles (most of them far more complicated than Sudoku's). See: https://www.iwriteiam.nl/Dpuzzle.html#EC https://www.iwriteiam.nl/Dpuzzle.html#EC for a list of blogs I wrote over the time.