Was your approach to randomly put a triangle in a cell and see if it works out or contradicts?If that's the approach,I am looking for something else because I did the same and it was very tiring. To elaborate ,how did you find which cell in R2C3 contains the triangle in the first place?

If there is a bottom/left triangle, it has 8 to the left. And the sum can be 15 or 21. In both cases R2C3 HAS to be 4. And then if you look at the triangle in R2C4 there is no way to make a perfect number. So the R2C3 has to have the upper/right triangle.

Checkout one Thropki Sudoku which I recently prepared for the practice of this test
http://www.funwithpuzzles.com/2016/02/thropki-sudoku.html

Can anyone tell me.....how a black triangle act as a symmetrical arrowhead and which arrowhead is pointing to the two digits?

It is the 90 degree corner of the triangle which acts as the point of the arrow (rather than either of the two 45 degree corners). Does this help?

In Max/Min Triplet Sums, I have identified the outside clue-whether max or min- but I am unable to figure out how to use this information as help in solving the Sudoku (apart from Classic rules) ? Please help..

Not able to figure out the two digits which is pointed by corresponding arrowhead.

Vishal,

Re: Max/Min Triplet Sums

I'm not very good at walkthroughs.

Try the following. Place two missing 8s by standard logic. Place 2s in boxes 6 and 7 by standard logic. Place 3 in box 8 by standard logic. Place 1 in box 3 by standard logic.

Now in row 4, the missing 1 cannot sit either side of the 3 and 2 (otherwise we would have a 6 sum in that row and we are told that 10 is the minimum sum) so it must go in column 2.

In the same row, the missing 5 must be either side of the 3 and 2 (otherwise we can't have a 10 sum). Therefore, column 3 in that row must have a 6.

In column 5, the 8 sum must be 1-3-4 in some order as the 2 is isolated. The 1 can't lie below the 3 as there would then be a 6 sum. So the 1 must go in row 5 and the 4 in row 6.

In box 4, the missing 3 can't go in bottom right corner as there would then be a 9 sum in row 6. So it goes immediately above that with the missing 4 to its left.

Then look at the 8 sum in column 3. etc.

Edited by David McNeill 2016-02-19 8:36 PM

Mihiryadav,

Re: Arrowhead

Consider the diagonally split cell in top right corner of box 5. The arrow cannot point to the south-east as the first digit in that direction is a 9 and the sum of the first two digits will therefore exceed the allowed value. So, the arrow must point to the north-west and the first two digits in this direction are 3 and 4, adding to 7. The top left triangle in our split cell is coloured black and a 7 is placed in the bottom right triangle.

Hope this gets you going.

How well did you like the theme of the contest?	I really liked the theme
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
Your 3 most favorite puzzles of the contest.	12. Renban Squeeze
Your 3 most favorite puzzles of the contest.	10. Tight Fit
Your 3 most favorite puzzles of the contest.	11. Non-Consecutive Squeeze

How well did you like the theme of the contest?	I somewhat liked the theme
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
Your 3 most favorite puzzles of the contest.	7. Max/Min Triplet Sums
Your 3 most favorite puzzles of the contest.	13. Triangular Sums
Your 3 most favorite puzzles of the contest.	4. Trio

This was a good test :) would have given it 3-stars if online solving was available - I don't have a printer so for puzzles without online solving I have to write all my answers in MSPaint with my mouse, which makes it take quite a bit longer and makes it difficult to write pencil marks.

Thanks David for your help and guiding me through the solving technique.. By the way, I failed to understand the rule - it was for all the combinations of consecutive numbers along a row and column; not only for the first 3...Thanks for your explanation..

How well did you like the theme of the contest?	I really liked the theme
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
Your 3 most favorite puzzles of the contest.	6. Outside Sums
Your 3 most favorite puzzles of the contest.	7. Max/Min Triplet Sums
Your 3 most favorite puzzles of the contest.	12. Renban Squeeze

How well did you like the theme of the contest?	I somewhat liked the theme
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
Your 3 most favorite puzzles of the contest.	9. Thropki
Your 3 most favorite puzzles of the contest.	14. Arrowhead
Your 3 most favorite puzzles of the contest.	10. Tight Fit

How well did you like the theme of the contest?	I somewhat liked the theme
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
Your 3 most favorite puzzles of the contest.	6. Outside Sums
Your 3 most favorite puzzles of the contest.	13. Triangular Sums
Your 3 most favorite puzzles of the contest.	9. Thropki

I really liked this test.Normally,I hate Math based variants in sudoku but this test was different.I remember thinking before the test that I would be happy with a score somewhere around 400.I didn't expect 470 in 90 mins(74?!).In the last 16 mins of the test,I really had a go at Thropki(100) but it seemed beyond my reach despite multiple guesses.

I greatly enjoyed solving Outside and Triangular sums both of which had a very systematic solve and I also loved the squeeze variants.

Thanks a lot to David for this wonderful test and to all test solvers. The set was delightful and I had great fun!

I have two questions on triangular sums:
1. Are we sure that we won't split any more cells? I am confused because the rule says triangles cannot touch grid boundary. These already placed ones are far enough not to touch :)
2. May the three numbers around a triangle be same?

Bskbri,

Re: Triangular Sums

All split cells will be indicated before solving.

There is no special rule prohibiting more than one edge of a triangle having the same digit.

How well did you like the theme of the contest?	I really liked the theme
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
Your 3 most favorite puzzles of the contest.	10. Tight Fit
Your 3 most favorite puzzles of the contest.	3. Classic
Your 3 most favorite puzzles of the contest.	6. Outside Sums

How well did you like the theme of the contest?	I somewhat liked the theme
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
Your 3 most favorite puzzles of the contest.	14. Arrowhead
Your 3 most favorite puzzles of the contest.	8. Thropki
Your 3 most favorite puzzles of the contest.	9. Thropki

I am unable to submit Classic-3 solution. The answer key is A - 249516837 and B - 847925316

Sorry, was typing the wrong answer I guess. The key was not allowing me to submit.

Edited by aashay 2016-02-20 10:27 PM

How well did you like the theme of the contest?	I really liked the theme
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
Your 3 most favorite puzzles of the contest.	5. Anti-Diagonal
Your 3 most favorite puzzles of the contest.	6. Outside Sums
Your 3 most favorite puzzles of the contest.	11. Non-Consecutive Squeeze

How well did you like the theme of the contest?	I really liked the theme
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
Your 3 most favorite puzzles of the contest.	9. Thropki

How well did you like the theme of the contest?	I somewhat liked the theme
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
Your 3 most favorite puzzles of the contest.	13. Triangular Sums
Your 3 most favorite puzzles of the contest.	9. Thropki
Your 3 most favorite puzzles of the contest.	14. Arrowhead

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
Your 3 most favorite puzzles of the contest.	5. Anti-Diagonal
Your 3 most favorite puzzles of the contest.	6. Outside Sums
Your 3 most favorite puzzles of the contest.	4. Trio

How well did you like the theme of the contest?	I really liked the theme
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
Your 3 most favorite puzzles of the contest.	8. Thropki
Your 3 most favorite puzzles of the contest.	7. Max/Min Triplet Sums
Your 3 most favorite puzzles of the contest.	6. Outside Sums