Wolves and sheep The 2019 Stack Overflow Developer Survey Results Are In Announcing the arrival of Valued Associate #679: Cesar Manara Planned maintenance scheduled April 17/18, 2019 at 00:00UTC (8:00pm US/Eastern)Fastest way to collect an arbitrary armyMiddle weight puzzleA puzzle of trust and lies, allies and spiesCooperative guessing against an evil godLabeling wires in a *damaged* bundleMonopoly Game Show: Is there a winning strategy?Picking A Number GamePrisoners and minority votingMove 10 sheep on another shoreBlindfold Bingo

Is every episode of "Where are my Pants?" identical?

Why can't devices on different VLANs, but on the same subnet, communicate?

What can I do if neighbor is blocking my solar panels intentionally?

Change bounding box of math glyphs in LuaTeX

How to test the equality of two Pearson correlation coefficients computed from the same sample?

Are my PIs rude or am I just being too sensitive?

Would an alien lifeform be able to achieve space travel if lacking in vision?

How can I define good in a religion that claims no moral authority?

Keeping a retro style to sci-fi spaceships?

How to politely respond to generic emails requesting a PhD/job in my lab? Without wasting too much time

Do warforged have souls?

Why did all the guest students take carriages to the Yule Ball?

Searching for a differential characteristic (differential cryptanalysis)

Semisimplicity of the category of coherent sheaves?

Working through the single responsibility principle (SRP) in Python when calls are expensive

How do I add random spotting to the same face in cycles?

How to copy the contents of all files with a certain name into a new file?

Match Roman Numerals

Finding the path in a graph from A to B then back to A with a minimum of shared edges

What do you call a plan that's an alternative plan in case your initial plan fails?

How do you keep chess fun when your opponent constantly beats you?

What is special about square numbers here?

How does ice melt when immersed in water?

What are these Gizmos at Izaña Atmospheric Research Center in Spain?



Wolves and sheep



The 2019 Stack Overflow Developer Survey Results Are In
Announcing the arrival of Valued Associate #679: Cesar Manara
Planned maintenance scheduled April 17/18, 2019 at 00:00UTC (8:00pm US/Eastern)Fastest way to collect an arbitrary armyMiddle weight puzzleA puzzle of trust and lies, allies and spiesCooperative guessing against an evil godLabeling wires in a *damaged* bundleMonopoly Game Show: Is there a winning strategy?Picking A Number GamePrisoners and minority votingMove 10 sheep on another shoreBlindfold Bingo










5












$begingroup$


All the sheep were living peacefully in the Land of Shewo. But suddenly they were struck by a danger. A few wolves dressed up as sheep entered the territory of Shewo and started killing the sheep one by one.



To find a solution to this misery, the king of Shewo called upon all of his sheep to the palace hall. He made the following announcement:




From my secret sources, I came to know that the total number of 'sheep' (including the wolves) now present in my kingdom is 100. Among which 5 are wolves. Our doctors have come up with a very expensive blood test which could be used to differentiate the wolves and sheep.



Each test costs 1000$ and we don't have enough funds to test all the 100 'sheep'.



I discussed with our ministers and came to know that the tests can be done on pooled bloodsamples. i.e., I can collect bloods from any number of 'sheep' and mix them. Then if I test the mixture, I will get a positive result if the mixture contain blood from any wolf. I will get a negative result if all the samples are from actual sheep.




One caveat is that the test results are available to you after all the tests are done!




Now , I am looking for ideas where I can find ALL the wolves in minimum number of pooled tests. I request the brilliant young minds of this land to come up with a testing strategy.




Can you help the king by devising a strategy?










share|improve this question









$endgroup$











  • $begingroup$
    This is close to a covering design (Lotto wheel) problem.
    $endgroup$
    – Arnaud Mortier
    3 hours ago










  • $begingroup$
    First of all, does the government have enough funds to test 99 of the sheep? Because that would work, at a cost of $99,000. Congrats, you just saved 1,000 bucks.
    $endgroup$
    – user45266
    59 mins ago











  • $begingroup$
    Alternatively, you know the location of all 5 wolves. Take initiative and slaughter all 100. Now you have no more wolves, and food for a good while to come.
    $endgroup$
    – user45266
    47 mins ago















5












$begingroup$


All the sheep were living peacefully in the Land of Shewo. But suddenly they were struck by a danger. A few wolves dressed up as sheep entered the territory of Shewo and started killing the sheep one by one.



To find a solution to this misery, the king of Shewo called upon all of his sheep to the palace hall. He made the following announcement:




From my secret sources, I came to know that the total number of 'sheep' (including the wolves) now present in my kingdom is 100. Among which 5 are wolves. Our doctors have come up with a very expensive blood test which could be used to differentiate the wolves and sheep.



Each test costs 1000$ and we don't have enough funds to test all the 100 'sheep'.



I discussed with our ministers and came to know that the tests can be done on pooled bloodsamples. i.e., I can collect bloods from any number of 'sheep' and mix them. Then if I test the mixture, I will get a positive result if the mixture contain blood from any wolf. I will get a negative result if all the samples are from actual sheep.




One caveat is that the test results are available to you after all the tests are done!




Now , I am looking for ideas where I can find ALL the wolves in minimum number of pooled tests. I request the brilliant young minds of this land to come up with a testing strategy.




Can you help the king by devising a strategy?










share|improve this question









$endgroup$











  • $begingroup$
    This is close to a covering design (Lotto wheel) problem.
    $endgroup$
    – Arnaud Mortier
    3 hours ago










  • $begingroup$
    First of all, does the government have enough funds to test 99 of the sheep? Because that would work, at a cost of $99,000. Congrats, you just saved 1,000 bucks.
    $endgroup$
    – user45266
    59 mins ago











  • $begingroup$
    Alternatively, you know the location of all 5 wolves. Take initiative and slaughter all 100. Now you have no more wolves, and food for a good while to come.
    $endgroup$
    – user45266
    47 mins ago













5












5








5





$begingroup$


All the sheep were living peacefully in the Land of Shewo. But suddenly they were struck by a danger. A few wolves dressed up as sheep entered the territory of Shewo and started killing the sheep one by one.



To find a solution to this misery, the king of Shewo called upon all of his sheep to the palace hall. He made the following announcement:




From my secret sources, I came to know that the total number of 'sheep' (including the wolves) now present in my kingdom is 100. Among which 5 are wolves. Our doctors have come up with a very expensive blood test which could be used to differentiate the wolves and sheep.



Each test costs 1000$ and we don't have enough funds to test all the 100 'sheep'.



I discussed with our ministers and came to know that the tests can be done on pooled bloodsamples. i.e., I can collect bloods from any number of 'sheep' and mix them. Then if I test the mixture, I will get a positive result if the mixture contain blood from any wolf. I will get a negative result if all the samples are from actual sheep.




One caveat is that the test results are available to you after all the tests are done!




Now , I am looking for ideas where I can find ALL the wolves in minimum number of pooled tests. I request the brilliant young minds of this land to come up with a testing strategy.




Can you help the king by devising a strategy?










share|improve this question









$endgroup$




All the sheep were living peacefully in the Land of Shewo. But suddenly they were struck by a danger. A few wolves dressed up as sheep entered the territory of Shewo and started killing the sheep one by one.



To find a solution to this misery, the king of Shewo called upon all of his sheep to the palace hall. He made the following announcement:




From my secret sources, I came to know that the total number of 'sheep' (including the wolves) now present in my kingdom is 100. Among which 5 are wolves. Our doctors have come up with a very expensive blood test which could be used to differentiate the wolves and sheep.



Each test costs 1000$ and we don't have enough funds to test all the 100 'sheep'.



I discussed with our ministers and came to know that the tests can be done on pooled bloodsamples. i.e., I can collect bloods from any number of 'sheep' and mix them. Then if I test the mixture, I will get a positive result if the mixture contain blood from any wolf. I will get a negative result if all the samples are from actual sheep.




One caveat is that the test results are available to you after all the tests are done!




Now , I am looking for ideas where I can find ALL the wolves in minimum number of pooled tests. I request the brilliant young minds of this land to come up with a testing strategy.




Can you help the king by devising a strategy?







strategy combinatorics algorithm






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked 4 hours ago









Jyotish RobinJyotish Robin

515112




515112











  • $begingroup$
    This is close to a covering design (Lotto wheel) problem.
    $endgroup$
    – Arnaud Mortier
    3 hours ago










  • $begingroup$
    First of all, does the government have enough funds to test 99 of the sheep? Because that would work, at a cost of $99,000. Congrats, you just saved 1,000 bucks.
    $endgroup$
    – user45266
    59 mins ago











  • $begingroup$
    Alternatively, you know the location of all 5 wolves. Take initiative and slaughter all 100. Now you have no more wolves, and food for a good while to come.
    $endgroup$
    – user45266
    47 mins ago
















  • $begingroup$
    This is close to a covering design (Lotto wheel) problem.
    $endgroup$
    – Arnaud Mortier
    3 hours ago










  • $begingroup$
    First of all, does the government have enough funds to test 99 of the sheep? Because that would work, at a cost of $99,000. Congrats, you just saved 1,000 bucks.
    $endgroup$
    – user45266
    59 mins ago











  • $begingroup$
    Alternatively, you know the location of all 5 wolves. Take initiative and slaughter all 100. Now you have no more wolves, and food for a good while to come.
    $endgroup$
    – user45266
    47 mins ago















$begingroup$
This is close to a covering design (Lotto wheel) problem.
$endgroup$
– Arnaud Mortier
3 hours ago




$begingroup$
This is close to a covering design (Lotto wheel) problem.
$endgroup$
– Arnaud Mortier
3 hours ago












$begingroup$
First of all, does the government have enough funds to test 99 of the sheep? Because that would work, at a cost of $99,000. Congrats, you just saved 1,000 bucks.
$endgroup$
– user45266
59 mins ago





$begingroup$
First of all, does the government have enough funds to test 99 of the sheep? Because that would work, at a cost of $99,000. Congrats, you just saved 1,000 bucks.
$endgroup$
– user45266
59 mins ago













$begingroup$
Alternatively, you know the location of all 5 wolves. Take initiative and slaughter all 100. Now you have no more wolves, and food for a good while to come.
$endgroup$
– user45266
47 mins ago




$begingroup$
Alternatively, you know the location of all 5 wolves. Take initiative and slaughter all 100. Now you have no more wolves, and food for a good while to come.
$endgroup$
– user45266
47 mins ago










2 Answers
2






active

oldest

votes


















1












$begingroup$

Here's my shot at it:




Pool 50 of the sheep. Of those 50, if the result comes back positive (wolf detected), split in half again, testing 25 pooled together. If this comes back positive, either 12 or 13 ofthe positive group. You see where this is going. Any negative results rule out all sheep in that group. Worst case scenario, it takes 54 tests (see image for explanation). Best case scenario, you get 14 tests. Price range: 14,000 - 54,000 dollars.




Not sure yet of the expected average, but I know this is better than 99 tests on average.



Diagram:




sheep.jpg




If this isn't the optimal solution, then my best bet on how to improve it would be to:




split into 1/5 the size of each group.







share|improve this answer









$endgroup$












  • $begingroup$
    I do not consider it much of a spoiler (there must be better algorithms) but the worst case scenario can be easily reduced to 35 tests. rot13(Qb ovanel frnepurf sbe bar jbys. Rnpu frnepu vf qbar ba nyy gur furrc zvahf jbysf sbhaq va gur cerivbhf frnepurf. Lbh jvyy arrq 5 frnepurf. Rnpu frnepu jvyy gnxr ng zbfg 7 grfgf. Fb gur jbefg pnfr fpranevb vf 35 grfgf).
    $endgroup$
    – ppgdev
    31 mins ago










  • $begingroup$
    Wait a minute, how would that work? Could you be a little more specific?
    $endgroup$
    – user45266
    29 mins ago










  • $begingroup$
    @ppgdev Like starting with 100, you split the group into 5 groups? What do you mean?
    $endgroup$
    – user45266
    28 mins ago










  • $begingroup$
    I moved my comment into an upper bound answer, with a more detailed explanation.
    $endgroup$
    – ppgdev
    11 mins ago


















0












$begingroup$

There must be better algorithms, but just to put an upper bound on a solution, the worst case scenario can be reduced to




35 tests. Do binary searches for one wolf. Each search is done on all the sheep minus wolfs found in the previous searches. So the first binary search is done on a set of all 100 'sheep'. You will find a wolf in no more than 7 tests. The next binary search is done on remaining 99 sheep. And so on. You will need 5 binary searches. Each search will take at most 7 tests. So the worst case scenario is 35 tests.







share|improve this answer









$endgroup$













    Your Answer








    StackExchange.ready(function()
    var channelOptions =
    tags: "".split(" "),
    id: "559"
    ;
    initTagRenderer("".split(" "), "".split(" "), channelOptions);

    StackExchange.using("externalEditor", function()
    // Have to fire editor after snippets, if snippets enabled
    if (StackExchange.settings.snippets.snippetsEnabled)
    StackExchange.using("snippets", function()
    createEditor();
    );

    else
    createEditor();

    );

    function createEditor()
    StackExchange.prepareEditor(
    heartbeatType: 'answer',
    autoActivateHeartbeat: false,
    convertImagesToLinks: false,
    noModals: true,
    showLowRepImageUploadWarning: true,
    reputationToPostImages: null,
    bindNavPrevention: true,
    postfix: "",
    imageUploader:
    brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
    contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
    allowUrls: true
    ,
    noCode: true, onDemand: true,
    discardSelector: ".discard-answer"
    ,immediatelyShowMarkdownHelp:true
    );



    );













    draft saved

    draft discarded


















    StackExchange.ready(
    function ()
    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fpuzzling.stackexchange.com%2fquestions%2f81737%2fwolves-and-sheep%23new-answer', 'question_page');

    );

    Post as a guest















    Required, but never shown

























    2 Answers
    2






    active

    oldest

    votes








    2 Answers
    2






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    1












    $begingroup$

    Here's my shot at it:




    Pool 50 of the sheep. Of those 50, if the result comes back positive (wolf detected), split in half again, testing 25 pooled together. If this comes back positive, either 12 or 13 ofthe positive group. You see where this is going. Any negative results rule out all sheep in that group. Worst case scenario, it takes 54 tests (see image for explanation). Best case scenario, you get 14 tests. Price range: 14,000 - 54,000 dollars.




    Not sure yet of the expected average, but I know this is better than 99 tests on average.



    Diagram:




    sheep.jpg




    If this isn't the optimal solution, then my best bet on how to improve it would be to:




    split into 1/5 the size of each group.







    share|improve this answer









    $endgroup$












    • $begingroup$
      I do not consider it much of a spoiler (there must be better algorithms) but the worst case scenario can be easily reduced to 35 tests. rot13(Qb ovanel frnepurf sbe bar jbys. Rnpu frnepu vf qbar ba nyy gur furrc zvahf jbysf sbhaq va gur cerivbhf frnepurf. Lbh jvyy arrq 5 frnepurf. Rnpu frnepu jvyy gnxr ng zbfg 7 grfgf. Fb gur jbefg pnfr fpranevb vf 35 grfgf).
      $endgroup$
      – ppgdev
      31 mins ago










    • $begingroup$
      Wait a minute, how would that work? Could you be a little more specific?
      $endgroup$
      – user45266
      29 mins ago










    • $begingroup$
      @ppgdev Like starting with 100, you split the group into 5 groups? What do you mean?
      $endgroup$
      – user45266
      28 mins ago










    • $begingroup$
      I moved my comment into an upper bound answer, with a more detailed explanation.
      $endgroup$
      – ppgdev
      11 mins ago















    1












    $begingroup$

    Here's my shot at it:




    Pool 50 of the sheep. Of those 50, if the result comes back positive (wolf detected), split in half again, testing 25 pooled together. If this comes back positive, either 12 or 13 ofthe positive group. You see where this is going. Any negative results rule out all sheep in that group. Worst case scenario, it takes 54 tests (see image for explanation). Best case scenario, you get 14 tests. Price range: 14,000 - 54,000 dollars.




    Not sure yet of the expected average, but I know this is better than 99 tests on average.



    Diagram:




    sheep.jpg




    If this isn't the optimal solution, then my best bet on how to improve it would be to:




    split into 1/5 the size of each group.







    share|improve this answer









    $endgroup$












    • $begingroup$
      I do not consider it much of a spoiler (there must be better algorithms) but the worst case scenario can be easily reduced to 35 tests. rot13(Qb ovanel frnepurf sbe bar jbys. Rnpu frnepu vf qbar ba nyy gur furrc zvahf jbysf sbhaq va gur cerivbhf frnepurf. Lbh jvyy arrq 5 frnepurf. Rnpu frnepu jvyy gnxr ng zbfg 7 grfgf. Fb gur jbefg pnfr fpranevb vf 35 grfgf).
      $endgroup$
      – ppgdev
      31 mins ago










    • $begingroup$
      Wait a minute, how would that work? Could you be a little more specific?
      $endgroup$
      – user45266
      29 mins ago










    • $begingroup$
      @ppgdev Like starting with 100, you split the group into 5 groups? What do you mean?
      $endgroup$
      – user45266
      28 mins ago










    • $begingroup$
      I moved my comment into an upper bound answer, with a more detailed explanation.
      $endgroup$
      – ppgdev
      11 mins ago













    1












    1








    1





    $begingroup$

    Here's my shot at it:




    Pool 50 of the sheep. Of those 50, if the result comes back positive (wolf detected), split in half again, testing 25 pooled together. If this comes back positive, either 12 or 13 ofthe positive group. You see where this is going. Any negative results rule out all sheep in that group. Worst case scenario, it takes 54 tests (see image for explanation). Best case scenario, you get 14 tests. Price range: 14,000 - 54,000 dollars.




    Not sure yet of the expected average, but I know this is better than 99 tests on average.



    Diagram:




    sheep.jpg




    If this isn't the optimal solution, then my best bet on how to improve it would be to:




    split into 1/5 the size of each group.







    share|improve this answer









    $endgroup$



    Here's my shot at it:




    Pool 50 of the sheep. Of those 50, if the result comes back positive (wolf detected), split in half again, testing 25 pooled together. If this comes back positive, either 12 or 13 ofthe positive group. You see where this is going. Any negative results rule out all sheep in that group. Worst case scenario, it takes 54 tests (see image for explanation). Best case scenario, you get 14 tests. Price range: 14,000 - 54,000 dollars.




    Not sure yet of the expected average, but I know this is better than 99 tests on average.



    Diagram:




    sheep.jpg




    If this isn't the optimal solution, then my best bet on how to improve it would be to:




    split into 1/5 the size of each group.








    share|improve this answer












    share|improve this answer



    share|improve this answer










    answered 49 mins ago









    user45266user45266

    32514




    32514











    • $begingroup$
      I do not consider it much of a spoiler (there must be better algorithms) but the worst case scenario can be easily reduced to 35 tests. rot13(Qb ovanel frnepurf sbe bar jbys. Rnpu frnepu vf qbar ba nyy gur furrc zvahf jbysf sbhaq va gur cerivbhf frnepurf. Lbh jvyy arrq 5 frnepurf. Rnpu frnepu jvyy gnxr ng zbfg 7 grfgf. Fb gur jbefg pnfr fpranevb vf 35 grfgf).
      $endgroup$
      – ppgdev
      31 mins ago










    • $begingroup$
      Wait a minute, how would that work? Could you be a little more specific?
      $endgroup$
      – user45266
      29 mins ago










    • $begingroup$
      @ppgdev Like starting with 100, you split the group into 5 groups? What do you mean?
      $endgroup$
      – user45266
      28 mins ago










    • $begingroup$
      I moved my comment into an upper bound answer, with a more detailed explanation.
      $endgroup$
      – ppgdev
      11 mins ago
















    • $begingroup$
      I do not consider it much of a spoiler (there must be better algorithms) but the worst case scenario can be easily reduced to 35 tests. rot13(Qb ovanel frnepurf sbe bar jbys. Rnpu frnepu vf qbar ba nyy gur furrc zvahf jbysf sbhaq va gur cerivbhf frnepurf. Lbh jvyy arrq 5 frnepurf. Rnpu frnepu jvyy gnxr ng zbfg 7 grfgf. Fb gur jbefg pnfr fpranevb vf 35 grfgf).
      $endgroup$
      – ppgdev
      31 mins ago










    • $begingroup$
      Wait a minute, how would that work? Could you be a little more specific?
      $endgroup$
      – user45266
      29 mins ago










    • $begingroup$
      @ppgdev Like starting with 100, you split the group into 5 groups? What do you mean?
      $endgroup$
      – user45266
      28 mins ago










    • $begingroup$
      I moved my comment into an upper bound answer, with a more detailed explanation.
      $endgroup$
      – ppgdev
      11 mins ago















    $begingroup$
    I do not consider it much of a spoiler (there must be better algorithms) but the worst case scenario can be easily reduced to 35 tests. rot13(Qb ovanel frnepurf sbe bar jbys. Rnpu frnepu vf qbar ba nyy gur furrc zvahf jbysf sbhaq va gur cerivbhf frnepurf. Lbh jvyy arrq 5 frnepurf. Rnpu frnepu jvyy gnxr ng zbfg 7 grfgf. Fb gur jbefg pnfr fpranevb vf 35 grfgf).
    $endgroup$
    – ppgdev
    31 mins ago




    $begingroup$
    I do not consider it much of a spoiler (there must be better algorithms) but the worst case scenario can be easily reduced to 35 tests. rot13(Qb ovanel frnepurf sbe bar jbys. Rnpu frnepu vf qbar ba nyy gur furrc zvahf jbysf sbhaq va gur cerivbhf frnepurf. Lbh jvyy arrq 5 frnepurf. Rnpu frnepu jvyy gnxr ng zbfg 7 grfgf. Fb gur jbefg pnfr fpranevb vf 35 grfgf).
    $endgroup$
    – ppgdev
    31 mins ago












    $begingroup$
    Wait a minute, how would that work? Could you be a little more specific?
    $endgroup$
    – user45266
    29 mins ago




    $begingroup$
    Wait a minute, how would that work? Could you be a little more specific?
    $endgroup$
    – user45266
    29 mins ago












    $begingroup$
    @ppgdev Like starting with 100, you split the group into 5 groups? What do you mean?
    $endgroup$
    – user45266
    28 mins ago




    $begingroup$
    @ppgdev Like starting with 100, you split the group into 5 groups? What do you mean?
    $endgroup$
    – user45266
    28 mins ago












    $begingroup$
    I moved my comment into an upper bound answer, with a more detailed explanation.
    $endgroup$
    – ppgdev
    11 mins ago




    $begingroup$
    I moved my comment into an upper bound answer, with a more detailed explanation.
    $endgroup$
    – ppgdev
    11 mins ago











    0












    $begingroup$

    There must be better algorithms, but just to put an upper bound on a solution, the worst case scenario can be reduced to




    35 tests. Do binary searches for one wolf. Each search is done on all the sheep minus wolfs found in the previous searches. So the first binary search is done on a set of all 100 'sheep'. You will find a wolf in no more than 7 tests. The next binary search is done on remaining 99 sheep. And so on. You will need 5 binary searches. Each search will take at most 7 tests. So the worst case scenario is 35 tests.







    share|improve this answer









    $endgroup$

















      0












      $begingroup$

      There must be better algorithms, but just to put an upper bound on a solution, the worst case scenario can be reduced to




      35 tests. Do binary searches for one wolf. Each search is done on all the sheep minus wolfs found in the previous searches. So the first binary search is done on a set of all 100 'sheep'. You will find a wolf in no more than 7 tests. The next binary search is done on remaining 99 sheep. And so on. You will need 5 binary searches. Each search will take at most 7 tests. So the worst case scenario is 35 tests.







      share|improve this answer









      $endgroup$















        0












        0








        0





        $begingroup$

        There must be better algorithms, but just to put an upper bound on a solution, the worst case scenario can be reduced to




        35 tests. Do binary searches for one wolf. Each search is done on all the sheep minus wolfs found in the previous searches. So the first binary search is done on a set of all 100 'sheep'. You will find a wolf in no more than 7 tests. The next binary search is done on remaining 99 sheep. And so on. You will need 5 binary searches. Each search will take at most 7 tests. So the worst case scenario is 35 tests.







        share|improve this answer









        $endgroup$



        There must be better algorithms, but just to put an upper bound on a solution, the worst case scenario can be reduced to




        35 tests. Do binary searches for one wolf. Each search is done on all the sheep minus wolfs found in the previous searches. So the first binary search is done on a set of all 100 'sheep'. You will find a wolf in no more than 7 tests. The next binary search is done on remaining 99 sheep. And so on. You will need 5 binary searches. Each search will take at most 7 tests. So the worst case scenario is 35 tests.








        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered 13 mins ago









        ppgdevppgdev

        41516




        41516



























            draft saved

            draft discarded
















































            Thanks for contributing an answer to Puzzling Stack Exchange!


            • Please be sure to answer the question. Provide details and share your research!

            But avoid


            • Asking for help, clarification, or responding to other answers.

            • Making statements based on opinion; back them up with references or personal experience.

            Use MathJax to format equations. MathJax reference.


            To learn more, see our tips on writing great answers.




            draft saved


            draft discarded














            StackExchange.ready(
            function ()
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fpuzzling.stackexchange.com%2fquestions%2f81737%2fwolves-and-sheep%23new-answer', 'question_page');

            );

            Post as a guest















            Required, but never shown





















































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown

































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown







            Popular posts from this blog

            یوتیوب محتویات پیشینه[ویرایش] فناوری‌های ویدئویی[ویرایش] شوخی‌های آوریل[ویرایش] سانسور و فیلترینگ[ویرایش] آمار و ارقامی از یوتیوب[ویرایش] تأثیر اجتماعی[ویرایش] سیاست اجتماعی[ویرایش] نمودارها[ویرایش] یادداشت‌ها[ویرایش] پانویس[ویرایش] پیوند به بیرون[ویرایش] منوی ناوبریبررسی شده‌استYouTube.com[بروزرسانی]"Youtube.com Site Info""زبان‌های یوتیوب""Surprise! There's a third YouTube co-founder"سایت یوتیوب برای چندمین بار در ایران فیلتر شدنسخهٔ اصلیسالار کمانگر جوان آمریکایی ایرانی الاصل مدیر سایت یوتیوب شدنسخهٔ اصلیVideo websites pop up, invite postingsthe originalthe originalYouTube: Overnight success has sparked a backlashthe original"Me at the zoo"YouTube serves up 100 million videos a day onlinethe originalcomScore Releases May 2010 U.S. Online Video Rankingsthe originalYouTube hits 4 billion daily video viewsthe originalYouTube users uploading two days of video every minutethe originalEric Schmidt, Princeton Colloquium on Public & Int'l Affairsthe original«Streaming Dreams»نسخهٔ اصلیAlexa Traffic Rank for YouTube (three month average)the originalHelp! YouTube is killing my business!the originalUtube sues YouTubethe originalGoogle closes $A2b YouTube dealthe originalFlash moves on to smart phonesthe originalYouTube HTML5 Video Playerنسخهٔ اصلیYouTube HTML5 Video Playerthe originalGoogle tries freeing Web video with WebMthe originalVideo length for uploadingthe originalYouTube caps video lengths to reduce infringementthe originalAccount Types: Longer videosthe originalYouTube bumps video limit to 15 minutesthe originalUploading large files and resumable uploadingthe originalVideo Formats: File formatsthe originalGetting Started: File formatsthe originalThe quest for a new video codec in Flash 8the originalAdobe Flash Video File Format Specification Version 10.1the originalYouTube Mobile goes livethe originalYouTube videos go HD with a simple hackthe originalYouTube now supports 4k-resolution videosthe originalYouTube to get high-def 1080p playerthe original«Approximate YouTube Bitrates»نسخهٔ اصلی«Bigger and Better: Encoding for YouTube 720p HD»نسخهٔ اصلی«YouTube's 1080p – Failure Depends on How You Look At It»نسخهٔ اصلیYouTube in 3Dthe originalYouTube in 3D?the originalYouTube 3D Videosthe originalYouTube adds a dimension, 3D goggles not includedthe originalYouTube Adds Stereoscopic 3D Video Support (And 3D Vision Support, Too)the original«Sharing YouTube Videos»نسخهٔ اصلی«Downloading videos from YouTube is not supported, except for one instance when it is permitted.»نسخهٔ اصلی«Terms of Use, 5.B»نسخهٔ اصلی«Some YouTube videos get download option»نسخهٔ اصلی«YouTube looks out for content owners, disables video ripping»«Downloading videos from YouTube is not supported, except for one instance when it is permitted.»نسخهٔ اصلی«YouTube Hopes To Boost Revenue With Video Downloads»نسخهٔ اصلی«YouTube Mobile»نسخهٔ اصلی«YouTube Live on Apple TV Today; Coming to iPhone on June 29»نسخهٔ اصلی«Goodbye Flash: YouTube mobile goes HTML5 on iPhone and Android»نسخهٔ اصلی«YouTube Mobile Goes HTML5, Video Quality Beats Native Apps Hands Down»نسخهٔ اصلی«TiVo Getting YouTube Streaming Today»نسخهٔ اصلی«YouTube video comes to Wii and PlayStation 3 game consoles»نسخهٔ اصلی«Coming Up Next... YouTube on Your TV»نسخهٔ اصلی«Experience YouTube XL on the Big Screen»نسخهٔ اصلی«Xbox Live Getting Live TV, YouTube & Bing Voice Search»نسخهٔ اصلی«YouTube content locations»نسخهٔ اصلی«April fools: YouTube turns the world up-side-down»نسخهٔ اصلی«YouTube goes back to 1911 for April Fools' Day»نسخهٔ اصلی«Simon Cowell's bromance, the self-driving Nascar and Hungry Hippos for iPad... the best April Fools' gags»نسخهٔ اصلی"YouTube Announces It Will Shut Down""YouTube Adds Darude 'Sandstorm' Button To Its Videos For April Fools' Day"«Censorship fears rise as Iran blocks access to top websites»نسخهٔ اصلی«China 'blocks YouTube video site'»نسخهٔ اصلی«YouTube shut down in Morocco»نسخهٔ اصلی«Thailand blocks access to YouTube»نسخهٔ اصلی«Ban on YouTube lifted after deal»نسخهٔ اصلی«Google's Gatekeepers»نسخهٔ اصلی«Turkey goes into battle with Google»نسخهٔ اصلی«Turkey lifts two-year ban on YouTube»نسخهٔ اصلیسانسور در ترکیه به یوتیوب رسیدلغو فیلترینگ یوتیوب در ترکیه«Pakistan blocks YouTube website»نسخهٔ اصلی«Pakistan lifts the ban on YouTube»نسخهٔ اصلی«Pakistan blocks access to YouTube in internet crackdown»نسخهٔ اصلی«Watchdog urges Libya to stop blocking websites»نسخهٔ اصلی«YouTube»نسخهٔ اصلی«Due to abuses of religion, customs Emirates, YouTube is blocked in the UAE»نسخهٔ اصلی«Google Conquered The Web - An Ultimate Winner»نسخهٔ اصلی«100 million videos are viewed daily on YouTube»نسخهٔ اصلی«Harry and Charlie Davies-Carr: Web gets taste for biting baby»نسخهٔ اصلی«Meet YouTube's 224 million girl, Natalie Tran»نسخهٔ اصلی«YouTube to Double Down on Its 'Channel' Experiment»نسخهٔ اصلی«13 Some Media Companies Choose to Profit From Pirated YouTube Clips»نسخهٔ اصلی«Irate HK man unlikely Web hero»نسخهٔ اصلی«Web Guitar Wizard Revealed at Last»نسخهٔ اصلی«Charlie bit my finger – again!»نسخهٔ اصلی«Lowered Expectations: Web Redefines 'Quality'»نسخهٔ اصلی«YouTube's 50 Greatest Viral Videos»نسخهٔ اصلیYouTube Community Guidelinesthe original«Why did my YouTube account get closed down?»نسخهٔ اصلی«Why do I have a sanction on my account?»نسخهٔ اصلی«Is YouTube's three-strike rule fair to users?»نسخهٔ اصلی«Viacom will sue YouTube for $1bn»نسخهٔ اصلی«Mediaset Files EUR500 Million Suit Vs Google's YouTube»نسخهٔ اصلی«Premier League to take action against YouTube»نسخهٔ اصلی«YouTube law fight 'threatens net'»نسخهٔ اصلی«Google must divulge YouTube log»نسخهٔ اصلی«Google Told to Turn Over User Data of YouTube»نسخهٔ اصلی«US judge tosses out Viacom copyright suit against YouTube»نسخهٔ اصلی«Google and Viacom: YouTube copyright lawsuit back on»نسخهٔ اصلی«Woman can sue over YouTube clip de-posting»نسخهٔ اصلی«YouTube loses court battle over music clips»نسخهٔ اصلیYouTube to Test Software To Ease Licensing Fightsthe original«Press Statistics»نسخهٔ اصلی«Testing YouTube's Audio Content ID System»نسخهٔ اصلی«Content ID disputes»نسخهٔ اصلیYouTube Community Guidelinesthe originalYouTube criticized in Germany over anti-Semitic Nazi videosthe originalFury as YouTube carries sick Hillsboro video insultthe originalYouTube attacked by MPs over sex and violence footagethe originalAl-Awlaki's YouTube Videos Targeted by Rep. Weinerthe originalYouTube Withdraws Cleric's Videosthe originalYouTube is letting users decide on terrorism-related videosthe original«Time's Person of the Year: You»نسخهٔ اصلی«Our top 10 funniest YouTube comments – what are yours?»نسخهٔ اصلی«YouTube's worst comments blocked by filter»نسخهٔ اصلی«Site Info YouTube»نسخهٔ اصلیوبگاه YouTubeوبگاه موبایل YouTubeوووووو

            Magento 2 - Auto login with specific URL Planned maintenance scheduled April 23, 2019 at 23:30 UTC (7:30pm US/Eastern) Announcing the arrival of Valued Associate #679: Cesar Manara Unicorn Meta Zoo #1: Why another podcast?Customer can't login - Page refreshes but nothing happensCustom Login page redirectURL to login with redirect URL after completionCustomer login is case sensitiveLogin with phone number or email address - Magento 1.9Magento 2: Set Customer Account Confirmation StatusCustomer auto connect from URLHow to call customer login form in the custom module action magento 2?Change of customer login error message magento2Referrer URL in modal login form

            Rest API with Magento using PHP with example. Planned maintenance scheduled April 17/18, 2019 at 00:00UTC (8:00pm US/Eastern) Announcing the arrival of Valued Associate #679: Cesar Manara Unicorn Meta Zoo #1: Why another podcast?How to update product using magento client library for PHP?Oauth Error while extending Magento Rest APINot showing my custom api in wsdl(url) and web service list?Using Magento API(REST) via IXMLHTTPRequest COM ObjectHow to login in Magento website using REST APIREST api call for Guest userMagento API calling using HTML and javascriptUse API rest media management by storeView code (admin)Magento REST API Example ErrorsHow to log all rest api calls in magento2?How to update product using magento client library for PHP?