## How to check solution and completed answers quickly?

Everything about Sudoku that doesn't fit in one of the other sections

### How to check solution and completed answers quickly?

Any suggestion on how to quickly cross-check the solution of a puzzle with our completed answer without going thru every row and coulums in the grid and yet ensure our answer is correct?

Thanks.
snowbear

Posts: 20
Joined: 27 October 2005

It's an eternal problem, and one that I don't think has any easy answer. If you've filled in a grid, then it's either right, or by definition you've got two numbers the same in a row/box/column. So unless you've checked every single cell, it could be the one you've not checked that's wrong.
PaulIQ164

Posts: 533
Joined: 16 July 2005

### search

good morning men and women,is there french people with me in this sudoku players forum.
see you later!
myra07700

Posts: 1
Joined: 29 November 2005

Paul's view of point is right for some, but some of us do solve our sudoku puzzles on a software grid (such as angus's "simple sudoku"), and while we don't use the hints it still guarantees we won't have any duplications on any row/column/box...

In that case I try to minimise the verifying time by comparing the grids box by box. So glance at box 1 of the solution, then compare my own box 1, then glance at my own box 2, then look back to box 2 of solution...

That way you don't even need to check the last box, so 16 glances is enough... nevertheless I always check box 9 anyway, just 2 more glances...

I find it much easier than comparing them row by row or column by column... but it takes some practice to "perceive" all the information of a 3x3 box in a single glance...
udosuk

Posts: 2698
Joined: 17 July 2005

The own method that I used so far is to focus on each 3X3 box one at a time, I check that each number from 1-9 is all inside the 3X3 box, then I proceed to the next box. Except at the beginning when I started to use this method and need to comfirm I got the answers correct, I now don't check with the published answer.

Is there any weakness in this approach?
snowbear

Posts: 20
Joined: 27 October 2005