We need to fill in a 9x9 grid with digits so that each column, row, and 3x3 section contain the numbers between 1 to 9.
Some squares are already filled in at start. Our job is to use logic to fill in the missing digits and complete the grid.
A digit is correct when:
- Each row contains NOT more than one of the same number from 1 to 9
- Each column contains NOT more than one of the same number from 1 to 9
- Each 3x3 grid contains NOT more than one of the same number from 1 to 9
The easiest way to begin is to choose a number and try to fill in all the places in the puzzle where it must appear, according to the Sudoku rules. …