Thread - Puzzle Solving Techniques

@ 2015-08-21 8:20 AM (#19107 - in reply to #19104) (#19107) Top

prasanna16391

Posts: 1812

Country : India

prasanna16391 posted @ 2015-08-21 8:20 AM

kishy72 - 2015-08-21 12:17 AM

Hi ghirsch. Thanks a lot for the starters.However,I am still not clear.How did you shade R2C5/C6/C7 and lots of other squares too.For instance ,why can't be a E present in R2C5 (East of South)

Because then S won't be South of E. Look at it both ways, simply.

@ 2015-08-22 12:07 AM (#19118 - in reply to #19107) (#19118) Top

kishy72

Posts: 419

Country : India

kishy72 posted @ 2015-08-22 12:07 AM

Thanks Swaroop and Prasanna ! I could proceed till here after which it's too difficult .Where am I missing the trick?

Edited by kishy72 2015-08-22 12:11 AM

@ 2015-08-22 2:06 AM (#19119 - in reply to #1525) (#19119) Top

rob

Posts: 170

Country : Germany

rob posted @ 2015-08-22 2:06 AM

The upside down L tetromino must have an N in the top row. Then you get an NW-pair in row 3.

@ 2015-08-22 3:02 AM (#19120 - in reply to #19119) (#19120) Top

kishy72

Posts: 419

Country : India

kishy72 posted @ 2015-08-22 3:02 AM

rob - 2015-08-22 2:06 AM

The upside down L tetromino must have an N in the top row. Then you get an NW-pair in row 3.

I don't see how the former leads to the latter?! Where is the NW pair that you refer in row 3?How did you deduce that?

@ 2015-08-22 10:56 PM (#19134 - in reply to #1525) (#19134) Top

swaroop2011

Posts: 668

Country : India

swaroop2011 posted @ 2015-08-22 10:56 PM

Hi kishy,
I haven't solved completely but looking at your image, I can tell you next few steps immediately:
1) R5C9 and R5C10 --> N will come in that region no matter what and in one of these places. (you can see what happens if N will not come)
2) Because of this R5C12 will be cross.
3) Now this gives N-W pair in Row 3, N or W at R3 -C5C6 AND N OR W at R3 C11-12.
4) So this eliminates N at R3 C1C2.
5) So this gives "S" at R5C1 and "E" at R3C2. So that will give "S" at r8c3.
I believe it should go easy after this.

@ 2015-08-22 11:38 PM (#19135 - in reply to #19134) (#19135) Top

kishy72

Posts: 419

Country : India

kishy72 posted @ 2015-08-22 11:38 PM

I can't thank you enough Swaroop.I have done and dusted the puzzle finally and that's a tremendous relief after breaking my head for close to 2 days.The way you explained about that NW Pair in point 3 made me see clearly what I failed to observe....

@ 2015-08-30 2:49 PM (#19202 - in reply to #1525) (#19202) Top

kishy72

Posts: 419

Country : India

kishy72 posted @ 2015-08-30 2:49 PM

A Numberlink puzzle.I realized that this puzzle has many ways of completing itself.Where am I going wrong?

Edited by kishy72 2015-08-30 2:50 PM

@ 2015-08-30 2:52 PM (#19203 - in reply to #19202) (#19203) Top

kishy72

Posts: 419

Country : India

kishy72 posted @ 2015-08-30 2:52 PM

In addition,in the above puzzle,I had to use the constraint that all cells need to be visited by paths without which I found 'n' number of ways of completing this puzzle.Is there something critical that I am missing here?

@ 2015-08-30 3:17 PM (#19204 - in reply to #19202) (#19204) Top

debmohanty

Country : India

debmohanty posted @ 2015-08-30 3:17 PM

kishy72 - 2015-08-30 2:49 PM

A Numberlink puzzle.I realized that this puzzle has many ways of completing itself.Where am I going wrong?

This was a broken puzzle (I suppose you have taken this from one old LMI test)

Talking about Numberlink in general, this write up (Numberlink Primer) by Palmer will be an eye-opener for most.

@ 2015-08-30 3:35 PM (#19205 - in reply to #19204) (#19205) Top

kishy72

Posts: 419

Country : India

kishy72 posted @ 2015-08-30 3:35 PM

This was a broken puzzle (I suppose you have taken this from one old LMI test)

Ah! I see.....It was taken from Nikoli Selection 2010 LMI monthly test.

Talking about Numberlink in general, this write up (Numberlink Primer) by Palmer will be an eye-opener for most.

Thanks a lot Deb!I will look through this primer.

@ 2015-08-31 6:45 PM (#19209 - in reply to #19205) (#19209) Top

kishy72

Posts: 419

Country : India

kishy72 posted @ 2015-08-31 6:45 PM

I ran into some problems in the following Hitori puzzle with just a few steps away from completion.Despite being so close,I fail to see a logical continuation here. Can someone post the solution ?

Edited by kishy72 2015-08-31 7:10 PM

@ 2015-08-31 8:07 PM (#19210 - in reply to #19209) (#19210) Top

swaroop2011

Posts: 668

Country : India

swaroop2011 posted @ 2015-08-31 8:07 PM

kishy72 - 2015-08-31 6:45 PM

I ran into some problems in the following Hitori puzzle with just a few steps away from completion.Despite being so close,I fail to see a logical continuation here. Can someone post the solution ?

one quick next step: R1C2 will be shaded.
Reason: Either of R8C1 or R8C2 will be shaded so that means R7C2 is unshaded in any case. Hence above step.

@ 2015-08-31 9:36 PM (#19211 - in reply to #19210) (#19211) Top

kishy72

Posts: 419

Country : India

kishy72 posted @ 2015-08-31 9:36 PM

swaroop2011 - 2015-08-31 8:07 PM

one quick next step: R1C2 will be shaded.
Reason: Either of R8C1 or R8C2 will be shaded so that means R7C2 is unshaded in any case. Hence above step.

Thank you ! I failed to see the 7 getting trapped.Done with the puzzle.

@ 2015-09-02 1:42 AM (#19216 - in reply to #19211) (#19216) Top

kishy72

Posts: 419

Country : India

kishy72 posted @ 2015-09-02 1:42 AM

A very difficult Hitori Puzzle ! Can someone please post the continuation here where I am stuck?

Edited by kishy72 2015-09-02 1:43 AM

@ 2015-09-02 2:18 AM (#19217 - in reply to #19216) (#19217) Top

swaroop2011

Posts: 668

Country : India

swaroop2011 posted @ 2015-09-02 2:18 AM

hi,
can you share the original puzzle link ?
I am confused whether what you have circled or not.
E.g. Is R6C5 "4" clue circled or not ?

@ 2015-09-02 2:59 AM (#19218 - in reply to #19217) (#19218) Top

kishy72

Posts: 419

Country : India

kishy72 posted @ 2015-09-02 2:59 AM

swaroop2011 - 2015-09-02 2:18 AM

hi,
can you share the original puzzle link ?
I am confused whether what you have circled or not.
E.g. Is R6C5 "4" clue circled or not ?

Sorry.You are right.It's not something which I deduced logically.I forgot to erase it.

@ 2015-09-02 8:57 AM (#19219 - in reply to #1525) (#19219) Top

ashaash11ash

Posts: 55

Country : India

ashaash11ash posted @ 2015-09-02 8:57 AM

R6c5 "4:" clue should be unshaded only.

@ 2015-09-02 9:18 AM (#19221 - in reply to #1525) (#19221) Top

ashaash11ash

Posts: 55

Country : India

ashaash11ash posted @ 2015-09-02 9:18 AM

If u see all the digits above and below the numbers at R7C5/7/9/11. for each number the digits above and below is same.. so if R6C5 is shaded then for the other numbers if any of the above or
below clue is shaded the white cells get closed at top

@ 2015-09-02 12:27 PM (#19225 - in reply to #19221) (#19225) Top

kishy72

Posts: 419

Country : India

kishy72 posted @ 2015-09-02 12:27 PM

ashaash11ash - 2015-09-02 9:18 AM

If u see all the digits above and below the numbers at R7C5/7/9/11. for each number the digits above and below is same.. so if R6C5 is shaded then for the other numbers if any of the above or
below clue is shaded the white cells get closed at top

Indeed.I missed this totally.The puzzle is still very sticky even after this deduction.But it helped a lot and I completed it .Thanks.

@ 2015-09-22 2:45 PM (#19441 - in reply to #1525) (#19441) Top

puzzleduniya

Posts: 56

Country : India

puzzleduniya posted @ 2015-09-22 2:45 PM

Just gone through the puzzle solving techniques. It's just amazing and very knowledgeable. I have learned a lot from it.

@ 2015-12-22 6:58 PM (#20328 - in reply to #1525) (#20328) Top

kishy72

Posts: 419

Country : India

kishy72 posted @ 2015-12-22 6:58 PM

The incorrectly done Mochikoro puzzle where all islands are not connected solved in the last few mins of the test .Apparently,there are ways one can gain points by solving incorrectly too !

Edited by kishy72 2015-12-22 6:59 PM

@ 2015-12-22 11:24 PM (#20332 - in reply to #1525) (#20332) Top

prasanna16391

Posts: 1812

Country : India

prasanna16391 posted @ 2015-12-22 11:24 PM

I too gained points by solving incorrectly, in a more indirect way. I solved the Japanese Sums 25 pointer incorrectly by placing a digit by mistake where it shouldn't be, which enabled me to reach an incorrect solution and move to the 105 pointer much faster than I would have if I had solved correctly. Considering I solved the 105 pointer with 1 minute to spare, I'd say the mistake gained me 80 points

@ 2015-12-22 11:54 PM (#20333 - in reply to #20332) (#20333) Top

swaroop2011

Posts: 668

Country : India

swaroop2011 posted @ 2015-12-22 11:54 PM

kishy72 - 2015-12-22 6:58 PM

The incorrectly done Mochikoro puzzle where all islands are not connected solved in the last few mins of the test .Apparently,there are ways one can gain points by solving incorrectly too !

prasanna16391 - 2015-12-22 11:24 PM

I too gained points by solving incorrectly, in a more indirect way. I solved the Japanese Sums 25 pointer incorrectly by placing a digit by mistake where it shouldn't be, which enabled me to reach an incorrect solution and move to the 105 pointer much faster than I would have if I had solved correctly. Considering I solved the 105 pointer with 1 minute to spare, I'd say the mistake gained me 80 points

haha interesting things.

@ 2016-01-28 8:02 PM (#20841 - in reply to #1525) (#20841) Top

brecher92

Posts: 30

Country : United States

brecher92 posted @ 2016-01-28 8:02 PM

Not sure where this question belongs, but I'm curious how much time a competitive puzzler might typically take to double-check their entries of the answer key during a timed competition. I just lost 78 points in GP Round 1 because I didn't double-check my entries. Do most people always set aside time at the end to double-check? Or after each puzzle? Or just continue to plow through the remaining puzzles and hope for the best?

@ 2016-01-28 10:16 PM (#20842 - in reply to #1525) (#20842) Top

prasanna16391

Posts: 1812

Country : India

prasanna16391 posted @ 2016-01-28 10:16 PM

For me I just plow through and hope for the best. My accuracy has improved in general with more experience though.


	@ 2015-08-21 8:20 AM (#19107 - in reply to #19104) (#19107) Top
prasanna16391 Posts: 1812 Country : India	prasanna16391 posted @ 2015-08-21 8:20 AM kishy72 - 2015-08-21 12:17 AM Hi ghirsch. Thanks a lot for the starters.However,I am still not clear.How did you shade R2C5/C6/C7 and lots of other squares too.For instance ,why can't be a E present in R2C5 (East of South) Because then S won't be South of E. Look at it both ways, simply.
	@ 2015-08-22 12:07 AM (#19118 - in reply to #19107) (#19118) Top
kishy72 Posts: 419 Country : India	kishy72 posted @ 2015-08-22 12:07 AM Thanks Swaroop and Prasanna ! I could proceed till here after which it's too difficult .Where am I missing the trick? Edited by kishy72 2015-08-22 12:11 AM
	@ 2015-08-22 2:06 AM (#19119 - in reply to #1525) (#19119) Top
rob Posts: 170 Country : Germany	rob posted @ 2015-08-22 2:06 AM The upside down L tetromino must have an N in the top row. Then you get an NW-pair in row 3.
	@ 2015-08-22 3:02 AM (#19120 - in reply to #19119) (#19120) Top
kishy72 Posts: 419 Country : India	kishy72 posted @ 2015-08-22 3:02 AM rob - 2015-08-22 2:06 AM The upside down L tetromino must have an N in the top row. Then you get an NW-pair in row 3. I don't see how the former leads to the latter?! Where is the NW pair that you refer in row 3?How did you deduce that?
	@ 2015-08-22 10:56 PM (#19134 - in reply to #1525) (#19134) Top
swaroop2011 Posts: 668 Country : India	swaroop2011 posted @ 2015-08-22 10:56 PM Hi kishy, I haven't solved completely but looking at your image, I can tell you next few steps immediately: 1) R5C9 and R5C10 --> N will come in that region no matter what and in one of these places. (you can see what happens if N will not come) 2) Because of this R5C12 will be cross. 3) Now this gives N-W pair in Row 3, N or W at R3 -C5C6 AND N OR W at R3 C11-12. 4) So this eliminates N at R3 C1C2. 5) So this gives "S" at R5C1 and "E" at R3C2. So that will give "S" at r8c3. I believe it should go easy after this.
	@ 2015-08-22 11:38 PM (#19135 - in reply to #19134) (#19135) Top
kishy72 Posts: 419 Country : India	kishy72 posted @ 2015-08-22 11:38 PM I can't thank you enough Swaroop.I have done and dusted the puzzle finally and that's a tremendous relief after breaking my head for close to 2 days.The way you explained about that NW Pair in point 3 made me see clearly what I failed to observe....
	@ 2015-08-30 2:49 PM (#19202 - in reply to #1525) (#19202) Top
kishy72 Posts: 419 Country : India	kishy72 posted @ 2015-08-30 2:49 PM A Numberlink puzzle.I realized that this puzzle has many ways of completing itself.Where am I going wrong? Edited by kishy72 2015-08-30 2:50 PM
	@ 2015-08-30 2:52 PM (#19203 - in reply to #19202) (#19203) Top
kishy72 Posts: 419 Country : India	kishy72 posted @ 2015-08-30 2:52 PM In addition,in the above puzzle,I had to use the constraint that all cells need to be visited by paths without which I found 'n' number of ways of completing this puzzle.Is there something critical that I am missing here?
	@ 2015-08-30 3:17 PM (#19204 - in reply to #19202) (#19204) Top
debmohanty Country : India	debmohanty posted @ 2015-08-30 3:17 PM kishy72 - 2015-08-30 2:49 PM A Numberlink puzzle.I realized that this puzzle has many ways of completing itself.Where am I going wrong? This was a broken puzzle (I suppose you have taken this from one old LMI test) Talking about Numberlink in general, this write up (Numberlink Primer) by Palmer will be an eye-opener for most.
	@ 2015-08-30 3:35 PM (#19205 - in reply to #19204) (#19205) Top
kishy72 Posts: 419 Country : India	kishy72 posted @ 2015-08-30 3:35 PM This was a broken puzzle (I suppose you have taken this from one old LMI test) Ah! I see.....It was taken from Nikoli Selection 2010 LMI monthly test. Talking about Numberlink in general, this write up (Numberlink Primer) by Palmer will be an eye-opener for most. Thanks a lot Deb!I will look through this primer.
	@ 2015-08-31 6:45 PM (#19209 - in reply to #19205) (#19209) Top
kishy72 Posts: 419 Country : India	kishy72 posted @ 2015-08-31 6:45 PM I ran into some problems in the following Hitori puzzle with just a few steps away from completion.Despite being so close,I fail to see a logical continuation here. Can someone post the solution ? Edited by kishy72 2015-08-31 7:10 PM
	@ 2015-08-31 8:07 PM (#19210 - in reply to #19209) (#19210) Top
swaroop2011 Posts: 668 Country : India	swaroop2011 posted @ 2015-08-31 8:07 PM kishy72 - 2015-08-31 6:45 PM I ran into some problems in the following Hitori puzzle with just a few steps away from completion.Despite being so close,I fail to see a logical continuation here. Can someone post the solution ? one quick next step: R1C2 will be shaded. Reason: Either of R8C1 or R8C2 will be shaded so that means R7C2 is unshaded in any case. Hence above step.
	@ 2015-08-31 9:36 PM (#19211 - in reply to #19210) (#19211) Top
kishy72 Posts: 419 Country : India	kishy72 posted @ 2015-08-31 9:36 PM swaroop2011 - 2015-08-31 8:07 PM kishy72 - 2015-08-31 6:45 PM I ran into some problems in the following Hitori puzzle with just a few steps away from completion.Despite being so close,I fail to see a logical continuation here. Can someone post the solution ? one quick next step: R1C2 will be shaded. Reason: Either of R8C1 or R8C2 will be shaded so that means R7C2 is unshaded in any case. Hence above step. Thank you ! I failed to see the 7 getting trapped.Done with the puzzle.
	@ 2015-09-02 1:42 AM (#19216 - in reply to #19211) (#19216) Top
kishy72 Posts: 419 Country : India	kishy72 posted @ 2015-09-02 1:42 AM A very difficult Hitori Puzzle ! Can someone please post the continuation here where I am stuck? Edited by kishy72 2015-09-02 1:43 AM
	@ 2015-09-02 2:18 AM (#19217 - in reply to #19216) (#19217) Top
swaroop2011 Posts: 668 Country : India	swaroop2011 posted @ 2015-09-02 2:18 AM hi, can you share the original puzzle link ? I am confused whether what you have circled or not. E.g. Is R6C5 "4" clue circled or not ?
	@ 2015-09-02 2:59 AM (#19218 - in reply to #19217) (#19218) Top
kishy72 Posts: 419 Country : India	kishy72 posted @ 2015-09-02 2:59 AM swaroop2011 - 2015-09-02 2:18 AM hi, can you share the original puzzle link ? I am confused whether what you have circled or not. E.g. Is R6C5 "4" clue circled or not ? Sorry.You are right.It's not something which I deduced logically.I forgot to erase it.
	@ 2015-09-02 8:57 AM (#19219 - in reply to #1525) (#19219) Top
ashaash11ash Posts: 55 Country : India	ashaash11ash posted @ 2015-09-02 8:57 AM R6c5 "4:" clue should be unshaded only.
	@ 2015-09-02 9:18 AM (#19221 - in reply to #1525) (#19221) Top
ashaash11ash Posts: 55 Country : India	ashaash11ash posted @ 2015-09-02 9:18 AM If u see all the digits above and below the numbers at R7C5/7/9/11. for each number the digits above and below is same.. so if R6C5 is shaded then for the other numbers if any of the above or below clue is shaded the white cells get closed at top
	@ 2015-09-02 12:27 PM (#19225 - in reply to #19221) (#19225) Top
kishy72 Posts: 419 Country : India	kishy72 posted @ 2015-09-02 12:27 PM ashaash11ash - 2015-09-02 9:18 AM If u see all the digits above and below the numbers at R7C5/7/9/11. for each number the digits above and below is same.. so if R6C5 is shaded then for the other numbers if any of the above or below clue is shaded the white cells get closed at top Indeed.I missed this totally.The puzzle is still very sticky even after this deduction.But it helped a lot and I completed it .Thanks.
	@ 2015-09-22 2:45 PM (#19441 - in reply to #1525) (#19441) Top
puzzleduniya Posts: 56 Country : India	puzzleduniya posted @ 2015-09-22 2:45 PM Just gone through the puzzle solving techniques. It's just amazing and very knowledgeable. I have learned a lot from it.
	@ 2015-12-22 6:58 PM (#20328 - in reply to #1525) (#20328) Top
kishy72 Posts: 419 Country : India	kishy72 posted @ 2015-12-22 6:58 PM The incorrectly done Mochikoro puzzle where all islands are not connected solved in the last few mins of the test .Apparently,there are ways one can gain points by solving incorrectly too ! Edited by kishy72 2015-12-22 6:59 PM
	@ 2015-12-22 11:24 PM (#20332 - in reply to #1525) (#20332) Top
prasanna16391 Posts: 1812 Country : India	prasanna16391 posted @ 2015-12-22 11:24 PM I too gained points by solving incorrectly, in a more indirect way. I solved the Japanese Sums 25 pointer incorrectly by placing a digit by mistake where it shouldn't be, which enabled me to reach an incorrect solution and move to the 105 pointer much faster than I would have if I had solved correctly. Considering I solved the 105 pointer with 1 minute to spare, I'd say the mistake gained me 80 points
	@ 2015-12-22 11:54 PM (#20333 - in reply to #20332) (#20333) Top
swaroop2011 Posts: 668 Country : India	swaroop2011 posted @ 2015-12-22 11:54 PM kishy72 - 2015-12-22 6:58 PM The incorrectly done Mochikoro puzzle where all islands are not connected solved in the last few mins of the test .Apparently,there are ways one can gain points by solving incorrectly too ! prasanna16391 - 2015-12-22 11:24 PM I too gained points by solving incorrectly, in a more indirect way. I solved the Japanese Sums 25 pointer incorrectly by placing a digit by mistake where it shouldn't be, which enabled me to reach an incorrect solution and move to the 105 pointer much faster than I would have if I had solved correctly. Considering I solved the 105 pointer with 1 minute to spare, I'd say the mistake gained me 80 points haha interesting things.
	@ 2016-01-28 8:02 PM (#20841 - in reply to #1525) (#20841) Top
brecher92 Posts: 30 Country : United States	brecher92 posted @ 2016-01-28 8:02 PM Not sure where this question belongs, but I'm curious how much time a competitive puzzler might typically take to double-check their entries of the answer key during a timed competition. I just lost 78 points in GP Round 1 because I didn't double-check my entries. Do most people always set aside time at the end to double-check? Or after each puzzle? Or just continue to plow through the remaining puzzles and hope for the best?
	@ 2016-01-28 10:16 PM (#20842 - in reply to #1525) (#20842) Top
prasanna16391 Posts: 1812 Country : India	prasanna16391 posted @ 2016-01-28 10:16 PM For me I just plow through and hope for the best. My accuracy has improved in general with more experience though.