Trying all the alternatives
List of contributions in 'Trial and Error - The Labyrinth'
| Trial and Error - The Labyrinth |
| If all else seems to fail you may need to do a trial and error approach for very tough Sudoku puzzles. Yes, this basically means you have to make a 'guess' of which of equally likely alternatives and see if it leads to a solution. If it turns out to be incorrect you'll need to backtrack - clearing all allocations made using that assumption until reaching a branch point when the choice was made. SudokuDragon makes this very easy actually as you can add a note to the square when you make the 'guess' explaining which branch was taken, you can then use the 'Undo' feature to take you all the way back to the decision point. It's really a strategy of last resort because it takes some time to undo it.
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| Guessing (3127) (re: Trial and Error - The Labyrinth) contributed by Jim Sheehan |
| How about placing a G after a puzzle that requires a guess?
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| Labyrinth Ban (re: Trial and Error - The Labyrinth) contributed by Prudence |
| I have heard and read that puzzles that require the use of a trial and error strategy are not considered genuine Sudoku puzzles. This page on Labyrinth Discussion goes into the ins and outs as to why one web site has decided to no longer offer puzzles that require a backtrack. Basically if a puzzle cant be solved by logical reasoning it shouldn't count as a Sudoku puzzle. Does SudokuDragon make this distinction I wonder?
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| Labyrinth Policy (re: Labyrinth Ban) contributed by SudokuDragon |
| It's a subject we are actively reviewing. With Release 2.7 (14) we have made sure none of our Moderate puzzles can ever require any backtracking. Many of the more difficult puzzles are also solvable using the straightforward Sudoku strategies (only place, forced choice, excluded subgroups and excluded twins). However some truly challenging puzzles although having a single solution may not be solvable using these techniques alone. Let us know what you would like to see. We are thinking of introducing an extra hard level of difficulty rather than banning the backtrack/labyrinth altogether.
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| Labyrinth Policy (2838) (re: Labyrinth Policy) contributed by SG |
| I prefer the puzzles to be able to be solved by logic. Using a trial and error method detracts from the game. I also owned a timed version of Sudoku and I spend considerable time on trying to find the logic to rationalize the answer. Having an extra hard category for logical puzzles without a stripe would be nice.
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| No backtracking (re: Labyrinth Policy (2838)) contributed by Alexander |
| Yes, I agree it's most frustrating to find out that there was no proper solution after all and have to resort to guessing rather than using pure logic to solve the puzzle. The vast majority of puzzles are now machine generated and perhaps that has something to do with it.
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| Submit865 (re: Trial and Error - The Labyrinth) contributed by Lynne |
Here's an example of a 'hard' puzzle that I can't find a way of solving without using backtracking Download this puzzle Click here to download this puzzle
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Any comments ? Other threads in this forum
C Shape
Cycles and Twins
Difficult Puzzles to Solve
Possibility Question
Is placing the correct candidates part of logic? (2745)
Is Sudoku a game Of mathematical symmetry?
Stripes
Three in a row (or column)
Two out of three lines
X-Wing
Online Forums
Advice and Suggestions for using SudokuDragon
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Help and advice on contributed Sudoku puzzles
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