data_structures.arrays.sudoku_solver
====================================

.. py:module:: data_structures.arrays.sudoku_solver

.. autoapi-nested-parse::

   Please do not modify this file!  It is published at https://norvig.com/sudoku.html with
   only minimal changes to work with modern versions of Python.  If you have improvements,
   please make them in a separate file.



Attributes
----------

.. autoapisummary::

   data_structures.arrays.sudoku_solver.cols
   data_structures.arrays.sudoku_solver.digits
   data_structures.arrays.sudoku_solver.grid1
   data_structures.arrays.sudoku_solver.grid2
   data_structures.arrays.sudoku_solver.hard1
   data_structures.arrays.sudoku_solver.peers
   data_structures.arrays.sudoku_solver.rows
   data_structures.arrays.sudoku_solver.squares
   data_structures.arrays.sudoku_solver.start
   data_structures.arrays.sudoku_solver.unitlist
   data_structures.arrays.sudoku_solver.units


Functions
---------

.. autoapisummary::

   data_structures.arrays.sudoku_solver.assign
   data_structures.arrays.sudoku_solver.cross
   data_structures.arrays.sudoku_solver.display
   data_structures.arrays.sudoku_solver.eliminate
   data_structures.arrays.sudoku_solver.from_file
   data_structures.arrays.sudoku_solver.grid_values
   data_structures.arrays.sudoku_solver.parse_grid
   data_structures.arrays.sudoku_solver.random_puzzle
   data_structures.arrays.sudoku_solver.search
   data_structures.arrays.sudoku_solver.shuffled
   data_structures.arrays.sudoku_solver.solve
   data_structures.arrays.sudoku_solver.solve_all
   data_structures.arrays.sudoku_solver.solved
   data_structures.arrays.sudoku_solver.some
   data_structures.arrays.sudoku_solver.test


Module Contents
---------------

.. py:function:: assign(values, s, d)

   Eliminate all the other values (except d) from values[s] and propagate.
   Return values, except return False if a contradiction is detected.


.. py:function:: cross(items_a, items_b)

   Cross product of elements in A and elements in B.


.. py:function:: display(values)

   Display these values as a 2-D grid.


.. py:function:: eliminate(values, s, d)

   Eliminate d from values[s]; propagate when values or places <= 2.
   Return values, except return False if a contradiction is detected.


.. py:function:: from_file(filename, sep='\n')

   Parse a file into a list of strings, separated by sep.


.. py:function:: grid_values(grid)

   Convert grid into a dict of {square: char} with '0' or '.' for empties.


.. py:function:: parse_grid(grid)

   Convert grid to a dict of possible values, {square: digits}, or
   return False if a contradiction is detected.


.. py:function:: random_puzzle(assignments=17)

   Make a random puzzle with N or more assignments. Restart on contradictions.
   Note the resulting puzzle is not guaranteed to be solvable, but empirically
   about 99.8% of them are solvable. Some have multiple solutions.


.. py:function:: search(values)

   Using depth-first search and propagation, try all possible values.


.. py:function:: shuffled(seq)

   Return a randomly shuffled copy of the input sequence.


.. py:function:: solve(grid)

   Solve the grid.


.. py:function:: solve_all(grids, name='', showif=0.0)

   Attempt to solve a sequence of grids. Report results.
   When showif is a number of seconds, display puzzles that take longer.
   When showif is None, don't display any puzzles.


.. py:function:: solved(values)

   A puzzle is solved if each unit is a permutation of the digits 1 to 9.


.. py:function:: some(seq)

   Return some element of seq that is true.


.. py:function:: test()

   A set of unit tests.


.. py:data:: cols
   :value: '123456789'


.. py:data:: digits
   :value: '123456789'


.. py:data:: grid1
   :value: '003020600900305001001806400008102900700000008006708200002609500800203009005010300'


.. py:data:: grid2
   :value: '4.....8.5.3..........7......2.....6.....8.4......1.......6.3.7.5..2.....1.4......'


.. py:data:: hard1
   :value: '.....6....59.....82....8....45........3........6..3.54...325..6..................'


.. py:data:: peers

.. py:data:: rows
   :value: 'ABCDEFGHI'


.. py:data:: squares

.. py:data:: start

.. py:data:: unitlist

.. py:data:: units