Snake Sum Sudoku 1
Normal sudoku rules apply except that the regions are irregular.
Additionally, a snake has to be drawn into the grid. The head and tail of the snake are in the two cells with the grey circles. The snake may not touch itself orthogonally, but it can touch itself diagonally.
The clues outside the grid indicate the sum of the digits located on the snake in the respective row/column. Considering "Snake" and "non-snake" as two colors, the given digits show how many cells orthogonally connected to the given are of a different color to the color of the given cell itself. All such possible digits are shown. NOTE: Digits placed by the solver CANNOT be true or they would have been given
Givens can be on or off the snake.
Here is a link to the puzzle on penpa
Lösungscode: All Digits Row 7 Left to Right
am 12. Juli 2020, 20:26 Uhr von Phistomefel
A lovely idea and fantastically executed. Thanks for this puzzle!
am 11. Juli 2020, 19:08 Uhr von henrypijames
@bob: Congrats! I really like this series of puzzles as well. As a preview: #2 has been the most enjoyable for me so far; #3 has a really hard sudoku (harder than this one) after drawing the snake; #4 is relatively easy; and upcoming #5 is supposed to super hard.
am 11. Juli 2020, 17:36 Uhr von Mody
Große Klasse, hat viel Spaß gemacht
am 11. Juli 2020, 14:29 Uhr von henrypijames
@bob: Your snake might be wrong, because you shouldn't be able to draw it without filling a bunch of digits in the process - the digits forcing the snake to be here and there. After drawing the snake, those digits you've already filled should help you do the sudoku (still not easy though).
And most importantly: Don't forget the negative constraint! Digits not given cannot be indicators of snake-parity of adjacent cells. That helps you eliminate some crucial possibilities for 1234. In fact, I now start every Snake Sum Sudoku by pencilling all possibilities of 123 (4 is a bit too unconstrained). By the time the snake is done (with the help of those 123 pencilmarks), usually more than half of all 123 are placed.
am 10. Juli 2020, 00:28 Uhr von bob
I'm pretty sure I located the snake, but am rewarded with a nearly impossible sudoku. Most of the sums provide little help.
am 27. Juni 2020, 16:16 Uhr von henrypijames
There is an image only if you switch to English, but if your site language is German there is no image.
am 27. Juni 2020, 15:58 Uhr von cdwg2000
Very Nice!The difficulty should have four stars.
am 27. Juni 2020, 15:58 Uhr von Quarterthru
If anyone is having trouble seeing the image here is a penpa link.
am 27. Juni 2020, 13:57 Uhr von henrypijames
There is no imagine of the grid? Even the HTML soucecode of this page shows no <img> within the puzzle description (so it's not image server down) - did you accidentally delete the grid when you edited the rules?
am 26. Juni 2020, 18:22 Uhr von Greg
@Big_Tiger:The numbers outside represent the sum of all digits that appear on the snake in that respective row or column.
am 26. Juni 2020, 18:12 Uhr von Big Tiger
I'm a little lost on exactly what the numbers outside the grid demonstrate.