A Sudoku puzzle consists of a nine-by-nine grid which is subdivided into nine three-by-three smaller grids. Given an incomplete grid, the goal is to complete it in such a way that each row contains the numbers 1 through 9 , each column contains the numbers 1 through 9 , and each three by three grid contains the numbers 1 through 9 as shown in the figure. If a graph were drawn with a vertex to represent each entry in the grid, what should the edges represent so that a nine-coloring of the graph would be a solution to the puzzle?

Transcribed Image Text:

Sudoku Puzzle 8 93 72 sa 9 21 96 4697 2 27 6 7 6 88 5 8 4 6 3 5 5 6 2 8 Solution to Puzzle 846937152 3 196 25847 75218496 3 2857 13694 4 6 3 8592 7 1 9 7 1 2 4 6 3 8 5 127598436 638471529 594362 7 1 8