If I can solve Sudoku, can I solve the Travelling Salesman Problem (TSP)? If so, how?When can a greedy algorithm solve the coin change problem?Finding the subset of $S$ that sums up to $k$ using a black box in $O(n)$ timeCan Euclidean TSP be exactly solved in time better than (sym)metric TSP?How to find partition set of a Partition Problem using its decision problemHow can we design an efficient warehouse management program?Finding vertices of a maximum clique in polynomial timeIs this an instance of a well-known problem?Is any sudoku solver an SAT solver?Applying a permutation on a sequence with multiplicationSolve this integer program (problem: Travelling salesman problem)

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This word with a lot of past tenses



If I can solve Sudoku, can I solve the Travelling Salesman Problem (TSP)? If so, how?


When can a greedy algorithm solve the coin change problem?Finding the subset of $S$ that sums up to $k$ using a black box in $O(n)$ timeCan Euclidean TSP be exactly solved in time better than (sym)metric TSP?How to find partition set of a Partition Problem using its decision problemHow can we design an efficient warehouse management program?Finding vertices of a maximum clique in polynomial timeIs this an instance of a well-known problem?Is any sudoku solver an SAT solver?Applying a permutation on a sequence with multiplicationSolve this integer program (problem: Travelling salesman problem)













12












$begingroup$


Let us say there is a program such that if you give a partially filled Sudoku of any size it gives you corresponding completed Sudoku.



Can you treat this program as a black box and use this to solve TSP? I mean is there a way to represent TSP problem as partially filled Sudoku, so that if I give you the answer of that Sudoku, you can tell the solution for TSP in polynomial time?



If yes, how? how do you represent TSP as a partially filled Sudoku and interpret corresponding filled Sudoku for the result.










share|cite|improve this question









New contributor




Chakrapani N Rao is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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$endgroup$







  • 6




    $begingroup$
    Nowhere on this page (in the question or either answer or comments) is "TSP" defined. Especially since this question is now on the Hot Network Questions list, a definition for outsiders would be a very nice addition.
    $endgroup$
    – Wildcard
    yesterday










  • $begingroup$
    @Wildcard done.
    $endgroup$
    – Chakrapani N Rao
    yesterday






  • 11




    $begingroup$
    @Wildcard Within computer science, it's so widely understood that TSP means "travelling salesman problem" that asking somebody to expand the abbreviation it is a bit like asking them to define "PC" on Super User. Sure, adding the definition doesn't hurt, but somebody who doesn't know the definition probably isn't going to get anything out of the question, anyway.
    $endgroup$
    – David Richerby
    23 hours ago






  • 4




    $begingroup$
    @DavidRicherby, I am quite familiar with the traveling salesman problem but have never encountered it by that acronym. Perhaps a better analogy than "PC" would be "IE." There are plenty of Windows users who use Internet Explorer who may never have encountered that acronym.
    $endgroup$
    – Wildcard
    22 hours ago






  • 5




    $begingroup$
    @DavidRicherby Just because someone isn't familiar with an acronym doesn't mean that they wouldn't get anything out of the question. And having it spelled out in the title helps searching.
    $endgroup$
    – Acccumulation
    21 hours ago















12












$begingroup$


Let us say there is a program such that if you give a partially filled Sudoku of any size it gives you corresponding completed Sudoku.



Can you treat this program as a black box and use this to solve TSP? I mean is there a way to represent TSP problem as partially filled Sudoku, so that if I give you the answer of that Sudoku, you can tell the solution for TSP in polynomial time?



If yes, how? how do you represent TSP as a partially filled Sudoku and interpret corresponding filled Sudoku for the result.










share|cite|improve this question









New contributor




Chakrapani N Rao is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$







  • 6




    $begingroup$
    Nowhere on this page (in the question or either answer or comments) is "TSP" defined. Especially since this question is now on the Hot Network Questions list, a definition for outsiders would be a very nice addition.
    $endgroup$
    – Wildcard
    yesterday










  • $begingroup$
    @Wildcard done.
    $endgroup$
    – Chakrapani N Rao
    yesterday






  • 11




    $begingroup$
    @Wildcard Within computer science, it's so widely understood that TSP means "travelling salesman problem" that asking somebody to expand the abbreviation it is a bit like asking them to define "PC" on Super User. Sure, adding the definition doesn't hurt, but somebody who doesn't know the definition probably isn't going to get anything out of the question, anyway.
    $endgroup$
    – David Richerby
    23 hours ago






  • 4




    $begingroup$
    @DavidRicherby, I am quite familiar with the traveling salesman problem but have never encountered it by that acronym. Perhaps a better analogy than "PC" would be "IE." There are plenty of Windows users who use Internet Explorer who may never have encountered that acronym.
    $endgroup$
    – Wildcard
    22 hours ago






  • 5




    $begingroup$
    @DavidRicherby Just because someone isn't familiar with an acronym doesn't mean that they wouldn't get anything out of the question. And having it spelled out in the title helps searching.
    $endgroup$
    – Acccumulation
    21 hours ago













12












12








12


4



$begingroup$


Let us say there is a program such that if you give a partially filled Sudoku of any size it gives you corresponding completed Sudoku.



Can you treat this program as a black box and use this to solve TSP? I mean is there a way to represent TSP problem as partially filled Sudoku, so that if I give you the answer of that Sudoku, you can tell the solution for TSP in polynomial time?



If yes, how? how do you represent TSP as a partially filled Sudoku and interpret corresponding filled Sudoku for the result.










share|cite|improve this question









New contributor




Chakrapani N Rao is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$




Let us say there is a program such that if you give a partially filled Sudoku of any size it gives you corresponding completed Sudoku.



Can you treat this program as a black box and use this to solve TSP? I mean is there a way to represent TSP problem as partially filled Sudoku, so that if I give you the answer of that Sudoku, you can tell the solution for TSP in polynomial time?



If yes, how? how do you represent TSP as a partially filled Sudoku and interpret corresponding filled Sudoku for the result.







algorithms np-complete reductions traveling-salesman sudoku






share|cite|improve this question









New contributor




Chakrapani N Rao is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|cite|improve this question









New contributor




Chakrapani N Rao is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









share|cite|improve this question




share|cite|improve this question








edited 2 hours ago









Rodrigo de Azevedo

700615




700615






New contributor




Chakrapani N Rao is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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asked yesterday









Chakrapani N RaoChakrapani N Rao

6918




6918




New contributor




Chakrapani N Rao is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.





New contributor





Chakrapani N Rao is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






Chakrapani N Rao is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







  • 6




    $begingroup$
    Nowhere on this page (in the question or either answer or comments) is "TSP" defined. Especially since this question is now on the Hot Network Questions list, a definition for outsiders would be a very nice addition.
    $endgroup$
    – Wildcard
    yesterday










  • $begingroup$
    @Wildcard done.
    $endgroup$
    – Chakrapani N Rao
    yesterday






  • 11




    $begingroup$
    @Wildcard Within computer science, it's so widely understood that TSP means "travelling salesman problem" that asking somebody to expand the abbreviation it is a bit like asking them to define "PC" on Super User. Sure, adding the definition doesn't hurt, but somebody who doesn't know the definition probably isn't going to get anything out of the question, anyway.
    $endgroup$
    – David Richerby
    23 hours ago






  • 4




    $begingroup$
    @DavidRicherby, I am quite familiar with the traveling salesman problem but have never encountered it by that acronym. Perhaps a better analogy than "PC" would be "IE." There are plenty of Windows users who use Internet Explorer who may never have encountered that acronym.
    $endgroup$
    – Wildcard
    22 hours ago






  • 5




    $begingroup$
    @DavidRicherby Just because someone isn't familiar with an acronym doesn't mean that they wouldn't get anything out of the question. And having it spelled out in the title helps searching.
    $endgroup$
    – Acccumulation
    21 hours ago












  • 6




    $begingroup$
    Nowhere on this page (in the question or either answer or comments) is "TSP" defined. Especially since this question is now on the Hot Network Questions list, a definition for outsiders would be a very nice addition.
    $endgroup$
    – Wildcard
    yesterday










  • $begingroup$
    @Wildcard done.
    $endgroup$
    – Chakrapani N Rao
    yesterday






  • 11




    $begingroup$
    @Wildcard Within computer science, it's so widely understood that TSP means "travelling salesman problem" that asking somebody to expand the abbreviation it is a bit like asking them to define "PC" on Super User. Sure, adding the definition doesn't hurt, but somebody who doesn't know the definition probably isn't going to get anything out of the question, anyway.
    $endgroup$
    – David Richerby
    23 hours ago






  • 4




    $begingroup$
    @DavidRicherby, I am quite familiar with the traveling salesman problem but have never encountered it by that acronym. Perhaps a better analogy than "PC" would be "IE." There are plenty of Windows users who use Internet Explorer who may never have encountered that acronym.
    $endgroup$
    – Wildcard
    22 hours ago






  • 5




    $begingroup$
    @DavidRicherby Just because someone isn't familiar with an acronym doesn't mean that they wouldn't get anything out of the question. And having it spelled out in the title helps searching.
    $endgroup$
    – Acccumulation
    21 hours ago







6




6




$begingroup$
Nowhere on this page (in the question or either answer or comments) is "TSP" defined. Especially since this question is now on the Hot Network Questions list, a definition for outsiders would be a very nice addition.
$endgroup$
– Wildcard
yesterday




$begingroup$
Nowhere on this page (in the question or either answer or comments) is "TSP" defined. Especially since this question is now on the Hot Network Questions list, a definition for outsiders would be a very nice addition.
$endgroup$
– Wildcard
yesterday












$begingroup$
@Wildcard done.
$endgroup$
– Chakrapani N Rao
yesterday




$begingroup$
@Wildcard done.
$endgroup$
– Chakrapani N Rao
yesterday




11




11




$begingroup$
@Wildcard Within computer science, it's so widely understood that TSP means "travelling salesman problem" that asking somebody to expand the abbreviation it is a bit like asking them to define "PC" on Super User. Sure, adding the definition doesn't hurt, but somebody who doesn't know the definition probably isn't going to get anything out of the question, anyway.
$endgroup$
– David Richerby
23 hours ago




$begingroup$
@Wildcard Within computer science, it's so widely understood that TSP means "travelling salesman problem" that asking somebody to expand the abbreviation it is a bit like asking them to define "PC" on Super User. Sure, adding the definition doesn't hurt, but somebody who doesn't know the definition probably isn't going to get anything out of the question, anyway.
$endgroup$
– David Richerby
23 hours ago




4




4




$begingroup$
@DavidRicherby, I am quite familiar with the traveling salesman problem but have never encountered it by that acronym. Perhaps a better analogy than "PC" would be "IE." There are plenty of Windows users who use Internet Explorer who may never have encountered that acronym.
$endgroup$
– Wildcard
22 hours ago




$begingroup$
@DavidRicherby, I am quite familiar with the traveling salesman problem but have never encountered it by that acronym. Perhaps a better analogy than "PC" would be "IE." There are plenty of Windows users who use Internet Explorer who may never have encountered that acronym.
$endgroup$
– Wildcard
22 hours ago




5




5




$begingroup$
@DavidRicherby Just because someone isn't familiar with an acronym doesn't mean that they wouldn't get anything out of the question. And having it spelled out in the title helps searching.
$endgroup$
– Acccumulation
21 hours ago




$begingroup$
@DavidRicherby Just because someone isn't familiar with an acronym doesn't mean that they wouldn't get anything out of the question. And having it spelled out in the title helps searching.
$endgroup$
– Acccumulation
21 hours ago










2 Answers
2






active

oldest

votes


















19












$begingroup$

For 9x9 Sudoku, no. It is finite so can be solved in $O(1)$ time.



But if you had a solver for $n^2 times n^2$ Sudoku, that worked for all $n$ and all possible partial boards, then yes, that could be used to solve TSP in polynomial time, as completing a $n^2 times n^2$ Sudoku is NP-complete.



The proof of NP-completeness works by reducing from some NP-complete problem R to Sudoku; then because R is NP-complete, you can reduce from TSP to R (that follows from the definition of NP-completeness); and chaining those reductions gives you a way to use the Sudoku solver to solve TSP.






share|cite|improve this answer











$endgroup$








  • 1




    $begingroup$
    Could you please explain how? Yes lets assume I have general sudoku solver which acts as a black box. So how can you use it? How do you represent TSP as a partially filled Sudoku
    $endgroup$
    – Chakrapani N Rao
    yesterday






  • 2




    $begingroup$
    @ChakrapaniNRao, see updated answer. Yes, I understand it is a black box. To work out the details, find the proof of NP-completeness for Sudoku and understand how the reduction works.
    $endgroup$
    – D.W.
    yesterday






  • 5




    $begingroup$
    @ChakrapaniNRao It doesn't answer the question completely but the full answer would be ridiculously long, be full of intricate details and wouldn't give you any more enlightenment than the sketch here. It's possible that a reduction of some NP-complete problem to $n^2times n^2$ sudoku might be interesting but, unless the proof that sudoku is NP-complete was actually by reduction from TSP (unlikely), the answer is still going to end "and then chain those two reductions together".
    $endgroup$
    – David Richerby
    yesterday










  • $begingroup$
    OK, so we do not have a working solution for the above question then?
    $endgroup$
    – Chakrapani N Rao
    yesterday






  • 4




    $begingroup$
    @ChakrapaniNRao You are asking how to solve problem X using a black box for problem Y. That is literally asking for a reduction. That's what "reduction" means. And, as this answer explains, the answer to your yes/no question is yes.
    $endgroup$
    – David Richerby
    23 hours ago


















13












$begingroup$

It is indeed possible to use a general Sudoku solver to solve instances of TSP, and if this solver takes polynomial time then the whole process will as well (in complexity terminology, there is a polynomial-time reduction from TSP to Sudoku). This is because Sudoku is NP-complete and TSP is in NP. But as is usually the case in this area, looking at the details of the reduction isn't particularly illuminating. If you want, you can piece it together by using the simple reduction from Latin square completion to Sudoku here, the reduction from triangulating uniform tripartite graphs to Latin square completion here, the reduction from 3SAT to triangulation here, and a formulation of TSP as a 3SAT problem. However, if you want to understand the idea behind reducing from Sudoku to TSP I think you would be better off studying Cook's theorem (showing that SAT is NP-complete) and a couple of simple reductions from 3SAT (e.g. to 3-dimensional matching) and being satisfied in the knowledge that the TSP-Sudoku reduction is just the same kind of thing but longer and more fiddly.






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    2 Answers
    2






    active

    oldest

    votes








    2 Answers
    2






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    19












    $begingroup$

    For 9x9 Sudoku, no. It is finite so can be solved in $O(1)$ time.



    But if you had a solver for $n^2 times n^2$ Sudoku, that worked for all $n$ and all possible partial boards, then yes, that could be used to solve TSP in polynomial time, as completing a $n^2 times n^2$ Sudoku is NP-complete.



    The proof of NP-completeness works by reducing from some NP-complete problem R to Sudoku; then because R is NP-complete, you can reduce from TSP to R (that follows from the definition of NP-completeness); and chaining those reductions gives you a way to use the Sudoku solver to solve TSP.






    share|cite|improve this answer











    $endgroup$








    • 1




      $begingroup$
      Could you please explain how? Yes lets assume I have general sudoku solver which acts as a black box. So how can you use it? How do you represent TSP as a partially filled Sudoku
      $endgroup$
      – Chakrapani N Rao
      yesterday






    • 2




      $begingroup$
      @ChakrapaniNRao, see updated answer. Yes, I understand it is a black box. To work out the details, find the proof of NP-completeness for Sudoku and understand how the reduction works.
      $endgroup$
      – D.W.
      yesterday






    • 5




      $begingroup$
      @ChakrapaniNRao It doesn't answer the question completely but the full answer would be ridiculously long, be full of intricate details and wouldn't give you any more enlightenment than the sketch here. It's possible that a reduction of some NP-complete problem to $n^2times n^2$ sudoku might be interesting but, unless the proof that sudoku is NP-complete was actually by reduction from TSP (unlikely), the answer is still going to end "and then chain those two reductions together".
      $endgroup$
      – David Richerby
      yesterday










    • $begingroup$
      OK, so we do not have a working solution for the above question then?
      $endgroup$
      – Chakrapani N Rao
      yesterday






    • 4




      $begingroup$
      @ChakrapaniNRao You are asking how to solve problem X using a black box for problem Y. That is literally asking for a reduction. That's what "reduction" means. And, as this answer explains, the answer to your yes/no question is yes.
      $endgroup$
      – David Richerby
      23 hours ago















    19












    $begingroup$

    For 9x9 Sudoku, no. It is finite so can be solved in $O(1)$ time.



    But if you had a solver for $n^2 times n^2$ Sudoku, that worked for all $n$ and all possible partial boards, then yes, that could be used to solve TSP in polynomial time, as completing a $n^2 times n^2$ Sudoku is NP-complete.



    The proof of NP-completeness works by reducing from some NP-complete problem R to Sudoku; then because R is NP-complete, you can reduce from TSP to R (that follows from the definition of NP-completeness); and chaining those reductions gives you a way to use the Sudoku solver to solve TSP.






    share|cite|improve this answer











    $endgroup$








    • 1




      $begingroup$
      Could you please explain how? Yes lets assume I have general sudoku solver which acts as a black box. So how can you use it? How do you represent TSP as a partially filled Sudoku
      $endgroup$
      – Chakrapani N Rao
      yesterday






    • 2




      $begingroup$
      @ChakrapaniNRao, see updated answer. Yes, I understand it is a black box. To work out the details, find the proof of NP-completeness for Sudoku and understand how the reduction works.
      $endgroup$
      – D.W.
      yesterday






    • 5




      $begingroup$
      @ChakrapaniNRao It doesn't answer the question completely but the full answer would be ridiculously long, be full of intricate details and wouldn't give you any more enlightenment than the sketch here. It's possible that a reduction of some NP-complete problem to $n^2times n^2$ sudoku might be interesting but, unless the proof that sudoku is NP-complete was actually by reduction from TSP (unlikely), the answer is still going to end "and then chain those two reductions together".
      $endgroup$
      – David Richerby
      yesterday










    • $begingroup$
      OK, so we do not have a working solution for the above question then?
      $endgroup$
      – Chakrapani N Rao
      yesterday






    • 4




      $begingroup$
      @ChakrapaniNRao You are asking how to solve problem X using a black box for problem Y. That is literally asking for a reduction. That's what "reduction" means. And, as this answer explains, the answer to your yes/no question is yes.
      $endgroup$
      – David Richerby
      23 hours ago













    19












    19








    19





    $begingroup$

    For 9x9 Sudoku, no. It is finite so can be solved in $O(1)$ time.



    But if you had a solver for $n^2 times n^2$ Sudoku, that worked for all $n$ and all possible partial boards, then yes, that could be used to solve TSP in polynomial time, as completing a $n^2 times n^2$ Sudoku is NP-complete.



    The proof of NP-completeness works by reducing from some NP-complete problem R to Sudoku; then because R is NP-complete, you can reduce from TSP to R (that follows from the definition of NP-completeness); and chaining those reductions gives you a way to use the Sudoku solver to solve TSP.






    share|cite|improve this answer











    $endgroup$



    For 9x9 Sudoku, no. It is finite so can be solved in $O(1)$ time.



    But if you had a solver for $n^2 times n^2$ Sudoku, that worked for all $n$ and all possible partial boards, then yes, that could be used to solve TSP in polynomial time, as completing a $n^2 times n^2$ Sudoku is NP-complete.



    The proof of NP-completeness works by reducing from some NP-complete problem R to Sudoku; then because R is NP-complete, you can reduce from TSP to R (that follows from the definition of NP-completeness); and chaining those reductions gives you a way to use the Sudoku solver to solve TSP.







    share|cite|improve this answer














    share|cite|improve this answer



    share|cite|improve this answer








    edited yesterday

























    answered yesterday









    D.W.D.W.

    101k12125289




    101k12125289







    • 1




      $begingroup$
      Could you please explain how? Yes lets assume I have general sudoku solver which acts as a black box. So how can you use it? How do you represent TSP as a partially filled Sudoku
      $endgroup$
      – Chakrapani N Rao
      yesterday






    • 2




      $begingroup$
      @ChakrapaniNRao, see updated answer. Yes, I understand it is a black box. To work out the details, find the proof of NP-completeness for Sudoku and understand how the reduction works.
      $endgroup$
      – D.W.
      yesterday






    • 5




      $begingroup$
      @ChakrapaniNRao It doesn't answer the question completely but the full answer would be ridiculously long, be full of intricate details and wouldn't give you any more enlightenment than the sketch here. It's possible that a reduction of some NP-complete problem to $n^2times n^2$ sudoku might be interesting but, unless the proof that sudoku is NP-complete was actually by reduction from TSP (unlikely), the answer is still going to end "and then chain those two reductions together".
      $endgroup$
      – David Richerby
      yesterday










    • $begingroup$
      OK, so we do not have a working solution for the above question then?
      $endgroup$
      – Chakrapani N Rao
      yesterday






    • 4




      $begingroup$
      @ChakrapaniNRao You are asking how to solve problem X using a black box for problem Y. That is literally asking for a reduction. That's what "reduction" means. And, as this answer explains, the answer to your yes/no question is yes.
      $endgroup$
      – David Richerby
      23 hours ago












    • 1




      $begingroup$
      Could you please explain how? Yes lets assume I have general sudoku solver which acts as a black box. So how can you use it? How do you represent TSP as a partially filled Sudoku
      $endgroup$
      – Chakrapani N Rao
      yesterday






    • 2




      $begingroup$
      @ChakrapaniNRao, see updated answer. Yes, I understand it is a black box. To work out the details, find the proof of NP-completeness for Sudoku and understand how the reduction works.
      $endgroup$
      – D.W.
      yesterday






    • 5




      $begingroup$
      @ChakrapaniNRao It doesn't answer the question completely but the full answer would be ridiculously long, be full of intricate details and wouldn't give you any more enlightenment than the sketch here. It's possible that a reduction of some NP-complete problem to $n^2times n^2$ sudoku might be interesting but, unless the proof that sudoku is NP-complete was actually by reduction from TSP (unlikely), the answer is still going to end "and then chain those two reductions together".
      $endgroup$
      – David Richerby
      yesterday










    • $begingroup$
      OK, so we do not have a working solution for the above question then?
      $endgroup$
      – Chakrapani N Rao
      yesterday






    • 4




      $begingroup$
      @ChakrapaniNRao You are asking how to solve problem X using a black box for problem Y. That is literally asking for a reduction. That's what "reduction" means. And, as this answer explains, the answer to your yes/no question is yes.
      $endgroup$
      – David Richerby
      23 hours ago







    1




    1




    $begingroup$
    Could you please explain how? Yes lets assume I have general sudoku solver which acts as a black box. So how can you use it? How do you represent TSP as a partially filled Sudoku
    $endgroup$
    – Chakrapani N Rao
    yesterday




    $begingroup$
    Could you please explain how? Yes lets assume I have general sudoku solver which acts as a black box. So how can you use it? How do you represent TSP as a partially filled Sudoku
    $endgroup$
    – Chakrapani N Rao
    yesterday




    2




    2




    $begingroup$
    @ChakrapaniNRao, see updated answer. Yes, I understand it is a black box. To work out the details, find the proof of NP-completeness for Sudoku and understand how the reduction works.
    $endgroup$
    – D.W.
    yesterday




    $begingroup$
    @ChakrapaniNRao, see updated answer. Yes, I understand it is a black box. To work out the details, find the proof of NP-completeness for Sudoku and understand how the reduction works.
    $endgroup$
    – D.W.
    yesterday




    5




    5




    $begingroup$
    @ChakrapaniNRao It doesn't answer the question completely but the full answer would be ridiculously long, be full of intricate details and wouldn't give you any more enlightenment than the sketch here. It's possible that a reduction of some NP-complete problem to $n^2times n^2$ sudoku might be interesting but, unless the proof that sudoku is NP-complete was actually by reduction from TSP (unlikely), the answer is still going to end "and then chain those two reductions together".
    $endgroup$
    – David Richerby
    yesterday




    $begingroup$
    @ChakrapaniNRao It doesn't answer the question completely but the full answer would be ridiculously long, be full of intricate details and wouldn't give you any more enlightenment than the sketch here. It's possible that a reduction of some NP-complete problem to $n^2times n^2$ sudoku might be interesting but, unless the proof that sudoku is NP-complete was actually by reduction from TSP (unlikely), the answer is still going to end "and then chain those two reductions together".
    $endgroup$
    – David Richerby
    yesterday












    $begingroup$
    OK, so we do not have a working solution for the above question then?
    $endgroup$
    – Chakrapani N Rao
    yesterday




    $begingroup$
    OK, so we do not have a working solution for the above question then?
    $endgroup$
    – Chakrapani N Rao
    yesterday




    4




    4




    $begingroup$
    @ChakrapaniNRao You are asking how to solve problem X using a black box for problem Y. That is literally asking for a reduction. That's what "reduction" means. And, as this answer explains, the answer to your yes/no question is yes.
    $endgroup$
    – David Richerby
    23 hours ago




    $begingroup$
    @ChakrapaniNRao You are asking how to solve problem X using a black box for problem Y. That is literally asking for a reduction. That's what "reduction" means. And, as this answer explains, the answer to your yes/no question is yes.
    $endgroup$
    – David Richerby
    23 hours ago











    13












    $begingroup$

    It is indeed possible to use a general Sudoku solver to solve instances of TSP, and if this solver takes polynomial time then the whole process will as well (in complexity terminology, there is a polynomial-time reduction from TSP to Sudoku). This is because Sudoku is NP-complete and TSP is in NP. But as is usually the case in this area, looking at the details of the reduction isn't particularly illuminating. If you want, you can piece it together by using the simple reduction from Latin square completion to Sudoku here, the reduction from triangulating uniform tripartite graphs to Latin square completion here, the reduction from 3SAT to triangulation here, and a formulation of TSP as a 3SAT problem. However, if you want to understand the idea behind reducing from Sudoku to TSP I think you would be better off studying Cook's theorem (showing that SAT is NP-complete) and a couple of simple reductions from 3SAT (e.g. to 3-dimensional matching) and being satisfied in the knowledge that the TSP-Sudoku reduction is just the same kind of thing but longer and more fiddly.






    share|cite|improve this answer








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    $endgroup$

















      13












      $begingroup$

      It is indeed possible to use a general Sudoku solver to solve instances of TSP, and if this solver takes polynomial time then the whole process will as well (in complexity terminology, there is a polynomial-time reduction from TSP to Sudoku). This is because Sudoku is NP-complete and TSP is in NP. But as is usually the case in this area, looking at the details of the reduction isn't particularly illuminating. If you want, you can piece it together by using the simple reduction from Latin square completion to Sudoku here, the reduction from triangulating uniform tripartite graphs to Latin square completion here, the reduction from 3SAT to triangulation here, and a formulation of TSP as a 3SAT problem. However, if you want to understand the idea behind reducing from Sudoku to TSP I think you would be better off studying Cook's theorem (showing that SAT is NP-complete) and a couple of simple reductions from 3SAT (e.g. to 3-dimensional matching) and being satisfied in the knowledge that the TSP-Sudoku reduction is just the same kind of thing but longer and more fiddly.






      share|cite|improve this answer








      New contributor




      rlms is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.






      $endgroup$















        13












        13








        13





        $begingroup$

        It is indeed possible to use a general Sudoku solver to solve instances of TSP, and if this solver takes polynomial time then the whole process will as well (in complexity terminology, there is a polynomial-time reduction from TSP to Sudoku). This is because Sudoku is NP-complete and TSP is in NP. But as is usually the case in this area, looking at the details of the reduction isn't particularly illuminating. If you want, you can piece it together by using the simple reduction from Latin square completion to Sudoku here, the reduction from triangulating uniform tripartite graphs to Latin square completion here, the reduction from 3SAT to triangulation here, and a formulation of TSP as a 3SAT problem. However, if you want to understand the idea behind reducing from Sudoku to TSP I think you would be better off studying Cook's theorem (showing that SAT is NP-complete) and a couple of simple reductions from 3SAT (e.g. to 3-dimensional matching) and being satisfied in the knowledge that the TSP-Sudoku reduction is just the same kind of thing but longer and more fiddly.






        share|cite|improve this answer








        New contributor




        rlms is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
        Check out our Code of Conduct.






        $endgroup$



        It is indeed possible to use a general Sudoku solver to solve instances of TSP, and if this solver takes polynomial time then the whole process will as well (in complexity terminology, there is a polynomial-time reduction from TSP to Sudoku). This is because Sudoku is NP-complete and TSP is in NP. But as is usually the case in this area, looking at the details of the reduction isn't particularly illuminating. If you want, you can piece it together by using the simple reduction from Latin square completion to Sudoku here, the reduction from triangulating uniform tripartite graphs to Latin square completion here, the reduction from 3SAT to triangulation here, and a formulation of TSP as a 3SAT problem. However, if you want to understand the idea behind reducing from Sudoku to TSP I think you would be better off studying Cook's theorem (showing that SAT is NP-complete) and a couple of simple reductions from 3SAT (e.g. to 3-dimensional matching) and being satisfied in the knowledge that the TSP-Sudoku reduction is just the same kind of thing but longer and more fiddly.







        share|cite|improve this answer








        New contributor




        rlms is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
        Check out our Code of Conduct.









        share|cite|improve this answer



        share|cite|improve this answer






        New contributor




        rlms is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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        answered 22 hours ago









        rlmsrlms

        23114




        23114




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        rlms is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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            Chakrapani N Rao is a new contributor. Be nice, and check out our Code of Conduct.









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