Sudoku strategy - Singles(Full House)

A house is a group of 9 cells which must contain all the numbers from 1 to 9, i.e a house can be a row, a column or a box.

A full house is such a group of 9 cells with one unsolved cell.


The figure above shows an example of a full house with a box with one unsolved cell. The missing number 9 is the solution to the unsolved cell.

For the program, the sole candidate method is sufficient to find any full house and so there is no need to implement extra methods for this strategy.