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Converse - 12th-15th Feb - Sudoku Mahabharat & ISC Qualifier74 posts • Page 1 of 3 • 1 2 3
@ 2016-02-12 7:44 AM (#20961 - in reply to #20869) (#20961) Top

shera90




Posts: 71
202020
Country : India

shera90 posted @ 2016-02-12 7:44 AM

Anybody give some clues on kropki sudoku 9*9 from IB. I want to know how to start as there are very few clues and I don't know where to start.

And also please give some starting clues for x sum frame 9*9 from IB.

Edited by shera90 2016-02-12 8:14 AM
@ 2016-02-12 8:24 AM (#20962 - in reply to #20961) (#20962) Top

rakesh_rai




Posts: 774
500100100202020
Country : India

rakesh_rai posted @ 2016-02-12 8:24 AM

shera90 - 2016-02-12 7:44 AM

Anybody give some clues on kropki sudoku 9*9 from IB. I want to know how to start as there are very few clues and I don't know where to start.

Look at column 4. Because of the 2s in col5 and col6, a 2 must come in C4R1 or C4R2 -> this means C4R1 and C4R2 must have the numbers 2 and 3. Then C4R4 has possible options as 5,6,7. 5 and 7 are not possible because of converse rule. So it must have the number 6. C4R6 now has possible options 5 or 7. If it is 7 then C4R8 and C4R9 will be 4 and 5, which is not possible. So C4R6 must be 5. Now C4R9 must be 4 as we have a black circle. And C4R7 is 7.

In general, try to start around black circles, as they are the most likely places to start. Then try to look for long consecutive sequences in a row/column/box. If you are stuck or there is less progress initially, some amount of pencilmarking around the marked circles can help get the breakthrough. After that make sure you do not forget classic rules AND converse rules. For example, if a cell has 3 and there are no circles then the neighbours cannot be 2,4, or 6.

I hope you will be able to solve this one now.
@ 2016-02-12 8:45 AM (#20963 - in reply to #20961) (#20963) Top

Guest



Guest posted @ 2016-02-12 8:45 AM

>>>And also please give some starting clues for x sum frame 9*9 from IB.

IB X sum frame 9x9: C4R4 = 4 (singlet). Concentrate on C5... C5R4 and C5R6 must contain (2,6). So, R5C4 and R5C6 must contain (3,8). Also observe that, C3R4 = C7R6 = 8.
@ 2016-02-12 8:59 AM (#20964 - in reply to #20963) (#20964) Top

rakesh_rai




Posts: 774
500100100202020
Country : India

rakesh_rai posted @ 2016-02-12 8:59 AM

Guest - 2016-02-12 8:45 AM

>>>And also please give some starting clues for x sum frame 9*9 from IB.

IB X sum frame 9x9: C4R4 = 4 (singlet). Concentrate on C5... C5R4 and C5R6 must contain (2,6). So, R5C4 and R5C6 must contain (3,8). Also observe that, C3R4 = C7R6 = 8.


Can you explain how you got (2,6) and (3,8) ?
@ 2016-02-12 9:01 AM (#20965 - in reply to #20964) (#20965) Top

rakesh_rai




Posts: 774
500100100202020
Country : India

rakesh_rai posted @ 2016-02-12 9:01 AM

>>>And also please give some starting clues for x sum frame 9*9 from IB.

The starting approach has to be to find the possibilities for X, without forgetting classic rules.

For example, in the IB, if we look at column 6, the first three numbers can have three numbers from 3,5,8 and 9. So the possible values of X are 16, 17, 20 or 22.

Now look at row 6. The possible values for first three numbers are 2,6,7,8 and 9. Using these numbers, we cannot make 20. So X cannot be 20. Also, if X=16, then we need to have 2,6 and 8 as first three numbers. Then we cannot place any number in R6C5. So X cannot be 16 either.

The possible values for X are now 17 or 22.

Similarly, you can deduct that X cannot be 17 as it leads to a contradiction in Boxes 4/5/6.

Once X is identified as 22, there are only two ways to make 22 (589 or 679). You will be able to solve easily after that.
@ 2016-02-12 11:11 AM (#20966 - in reply to #20965) (#20966) Top

harmeets



harmeets posted @ 2016-02-12 11:11 AM

>>>Can you explain how you got (2,6) and (3,8) ?

In column C5, the middle 3 numbers (in r4,r5,r6) must add up to 12. Two numbers are 4 and 2, so 3rd one must be 6.
Why the middle numbers add to 12? Because in C5, 1st 3 numbers (r1,r2,r3) = (45 - X - 12), and last 3 numbers (r7,r8,r9) = X. So middle 3 numbers = (45 - (45 - X - 12) - X) = 12.
@ 2016-02-12 4:03 PM (#20967 - in reply to #20869) (#20967) Top

vopani



Posts: 739
50010010020
Country : India

vopani posted @ 2016-02-12 4:03 PM

 How well did the variants represent the theme of the test ? variations represented the theme well
 What was your opinion of the distribution of easy/hard puzzles? Just right
 What did you think about the puzzle quality of the test? Very nice
 Which set of puzzles did you like the most? QuadMax 4Odd 4Even
 Of the puzzles you solved/attempted, how well did the point values reflect the difficulty? Many puzzles were worth too much or too little


Really nice sudokus!
I was lost on both the Average sudokus... but otherwise it went smooth.
QuadMax 9x9 and X-Frame 9x9 were my favourites.

Thanks Harmeet and Rakesh.
@ 2016-02-12 4:12 PM (#20968 - in reply to #20869) (#20968) Top

An LMI player



An LMI player posted @ 2016-02-12 4:12 PM

 How well did the variants represent the theme of the test ? variations represented the theme well
 What was your opinion of the distribution of easy/hard puzzles? Just right
 What did you think about the puzzle quality of the test? Fairly Nice
 Which set of puzzles did you like the most? QuadMax 4Odd 4Even
 Of the puzzles you solved/attempted, how well did the point values reflect the difficulty? Most puzzles were worth the right amount


@ 2016-02-12 5:29 PM (#20969 - in reply to #20869) (#20969) Top

marred



Posts: 12

Country : Poland

marred posted @ 2016-02-12 5:29 PM

 How well did the variants represent the theme of the test ? were not represented well
 What was your opinion of the distribution of easy/hard puzzles? Too many hard puzzles
 What did you think about the puzzle quality of the test? Below Average
 Which set of puzzles did you like the most? Classic Sudoku
 Of the puzzles you solved/attempted, how well did the point values reflect the difficulty? Most puzzles were worth too much or too little


@ 2016-02-12 7:49 PM (#20970 - in reply to #20869) (#20970) Top

An LMI player



An LMI player posted @ 2016-02-12 7:49 PM

 How well did the variants represent the theme of the test ? variations represented the theme well
 What was your opinion of the distribution of easy/hard puzzles? Too many hard puzzles
 What did you think about the puzzle quality of the test? Fairly Nice
 Which set of puzzles did you like the most? QuadMax 4Odd 4Even
 Of the puzzles you solved/attempted, how well did the point values reflect the difficulty? Most puzzles were worth the right amount


@ 2016-02-12 10:13 PM (#20971 - in reply to #20869) (#20971) Top

An LMI player



An LMI player posted @ 2016-02-12 10:13 PM

 How well did the variants represent the theme of the test ? variations represented the theme well
 What was your opinion of the distribution of easy/hard puzzles? Too many hard puzzles
 What did you think about the puzzle quality of the test? Fairly Nice
 Which set of puzzles did you like the most? X Sum Frame Sudoku
 Of the puzzles you solved/attempted, how well did the point values reflect the difficulty? Many puzzles were worth too much or too little


@ 2016-02-12 10:40 PM (#20972 - in reply to #20869) (#20972) Top

margareta456



Posts: 30
20
Country : Poland

margareta456 posted @ 2016-02-12 10:40 PM

 How well did the variants represent the theme of the test ? variations represented the theme well
 What was your opinion of the distribution of easy/hard puzzles? Too many hard puzzles
 What did you think about the puzzle quality of the test? Very nice
 Which set of puzzles did you like the most? Consecutive Sudoku
 Of the puzzles you solved/attempted, how well did the point values reflect the difficulty? Most puzzles were worth the right amount


@ 2016-02-12 10:46 PM (#20973 - in reply to #20869) (#20973) Top

MrLiang




Posts: 44
2020
Country : Thailand

MrLiang posted @ 2016-02-12 10:46 PM

 How well did the variants represent the theme of the test ? variations represented the theme well
 What was your opinion of the distribution of easy/hard puzzles? Just right
 What did you think about the puzzle quality of the test? Very nice
 Which set of puzzles did you like the most? X Sum Frame Sudoku
 Of the puzzles you solved/attempted, how well did the point values reflect the difficulty? Most puzzles were worth the right amount


@ 2016-02-13 12:40 AM (#20975 - in reply to #20869) (#20975) Top

Swagatam



Posts: 45
2020
Country : India

Swagatam posted @ 2016-02-13 12:40 AM

 How well did the variants represent the theme of the test ? variations represented the theme well
 What was your opinion of the distribution of easy/hard puzzles? Too many hard puzzles
 What did you think about the puzzle quality of the test? Average
 Of the puzzles you solved/attempted, how well did the point values reflect the difficulty? Many puzzles were worth too much or too little


@ 2016-02-13 3:15 AM (#20976 - in reply to #20869) (#20976) Top

wgryciuk



Posts: 24
20
Country : Poland

wgryciuk posted @ 2016-02-13 3:15 AM

 How well did the variants represent the theme of the test ? variations represented the theme well
 What was your opinion of the distribution of easy/hard puzzles? Just right
 What did you think about the puzzle quality of the test? Very nice
 Which set of puzzles did you like the most? Consecutive Sudoku
 Of the puzzles you solved/attempted, how well did the point values reflect the difficulty? Most puzzles were worth the right amount


@ 2016-02-13 3:20 AM (#20977 - in reply to #20869) (#20977) Top

David McNeill



Posts: 63
202020
Country : United Kingdom

David McNeill posted @ 2016-02-13 3:20 AM

 How well did the variants represent the theme of the test ? variations represented the theme well
 What was your opinion of the distribution of easy/hard puzzles? Just right
 What did you think about the puzzle quality of the test? Very nice
 Which set of puzzles did you like the most? QuadMax 4Odd 4Even
 Of the puzzles you solved/attempted, how well did the point values reflect the difficulty? Most puzzles were worth the right amount


@ 2016-02-13 3:23 PM (#20979 - in reply to #20869) (#20979) Top

RameshLMI



Posts: 51
2020
Country : India

RameshLMI posted @ 2016-02-13 3:23 PM

 How well did the variants represent the theme of the test ? variations represented the theme well
 What was your opinion of the distribution of easy/hard puzzles? Too many hard puzzles
 What did you think about the puzzle quality of the test? Very nice
 Which set of puzzles did you like the most? X Sum Frame Sudoku
 Of the puzzles you solved/attempted, how well did the point values reflect the difficulty? Most puzzles were worth the right amount


@ 2016-02-13 5:14 PM (#20980 - in reply to #20869) (#20980) Top

Vishal



Posts: 22
20
Country : India

Vishal posted @ 2016-02-13 5:14 PM

 How well did the variants represent the theme of the test ? representation could have been better
 What was your opinion of the distribution of easy/hard puzzles? Too many hard puzzles
 What did you think about the puzzle quality of the test? Fairly Nice
 Which set of puzzles did you like the most? QuadMax 4Odd 4Even
 Of the puzzles you solved/attempted, how well did the point values reflect the difficulty? Most puzzles were worth too much or too little


@ 2016-02-13 6:29 PM (#20981 - in reply to #20869) (#20981) Top

TiiT



Posts: 139
10020
Country : Estonia

TiiT posted @ 2016-02-13 6:29 PM

 How well did the variants represent the theme of the test ? variations represented the theme well
 What was your opinion of the distribution of easy/hard puzzles? Just right
 What did you think about the puzzle quality of the test? Below Average
 Which set of puzzles did you like the most? QuadMax 4Odd 4Even
 Of the puzzles you solved/attempted, how well did the point values reflect the difficulty? Most puzzles were worth the right amount


@ 2016-02-13 10:05 PM (#20984 - in reply to #20869) (#20984) Top

ghirsch



Posts: 102
100
Country : United States

ghirsch posted @ 2016-02-13 10:05 PM

 How well did the variants represent the theme of the test ? variations represented the theme well
 What was your opinion of the distribution of easy/hard puzzles? Just right
 What did you think about the puzzle quality of the test? Very nice
 Which set of puzzles did you like the most? X Sum Frame Sudoku
 Of the puzzles you solved/attempted, how well did the point values reflect the difficulty? Most puzzles were worth the right amount


Thanks for another great test Rakesh and Harmeet. All of the puzzles I solved were very nice, but my favorites were QuadMax 2 and X Sum Frame 2 (I really liked the deductions for X in this one).
@ 2016-02-13 11:14 PM (#20985 - in reply to #20869) (#20985) Top

gaurav.kjain



Posts: 52
2020
Country : India

gaurav.kjain posted @ 2016-02-13 11:14 PM

Really nice sudokus....Liked construction of all of them.
Hats off, Rakesh and Harmeet.
Kropki seems to be a no starter for me logically, Rakesh/Harmeet, please provide me THE logical starting point.

Technically for me 2015-16 SM is ended as, I will be co-authoring last round of SM along with Amit.
All the rounds were really great and I enjoyed them a lot. Thanks for the authors and organizers for all great SM rounds throughout the year.

@ 2016-02-13 11:54 PM (#20986 - in reply to #20985) (#20986) Top

rakesh_rai




Posts: 774
500100100202020
Country : India

rakesh_rai posted @ 2016-02-13 11:54 PM

gaurav.kjain - 2016-02-13 11:14 PM

Kropki seems to be a no starter for me logically, Rakesh/Harmeet, please provide me THE logical starting point.
I guess you are referring to the 9x9.
(1) One starting point is R1C3/C4 -> one of them has to be 3. You can find out easily that the 3 must go in R1C4. You can then fill out all cells in row 1. R1C1 cannot be 5 (look at the long sequence in col 1) so it will be 1.
(2) R5C1 is even (count odd/even in box4). Using this, we can complete col 1, as there is only one place for the number 2.

After this, it should be simpler.
@ 2016-02-14 12:20 AM (#20988 - in reply to #20869) (#20988) Top

detuned



Posts: 152
1002020
Country : United Kingdom

detuned posted @ 2016-02-14 12:20 AM

 How well did the variants represent the theme of the test ? representation could have been better
 What did you think about the puzzle quality of the test? Fairly Nice
 Which set of puzzles did you like the most? Classic Sudoku
 Of the puzzles you solved/attempted, how well did the point values reflect the difficulty? Most puzzles were worth the right amount


@ 2016-02-14 1:16 AM (#20989 - in reply to #20869) (#20989) Top

kishy72



Posts: 417
100100100100
Country : India

kishy72 posted @ 2016-02-14 1:16 AM

 How well did the variants represent the theme of the test ? representation could have been better
 What was your opinion of the distribution of easy/hard puzzles? Too many hard puzzles
 What did you think about the puzzle quality of the test? Fairly Nice
 Which set of puzzles did you like the most? QuadMax 4Odd 4Even
 Of the puzzles you solved/attempted, how well did the point values reflect the difficulty? Most puzzles were worth the right amount


@ 2016-02-14 1:51 AM (#20990 - in reply to #20869) (#20990) Top

An LMI player



An LMI player posted @ 2016-02-14 1:51 AM

 How well did the variants represent the theme of the test ? variations represented the theme well
 What did you think about the puzzle quality of the test? Very nice
 Which set of puzzles did you like the most? X Sum Frame Sudoku
 Of the puzzles you solved/attempted, how well did the point values reflect the difficulty? Many puzzles were worth too much or too little


Converse - 12th-15th Feb - Sudoku Mahabharat & ISC Qualifier74 posts • Page 1 of 3 • 1 2 3
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