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Butterfly X Nurikabe Killer http://www.rcbroughton.co.uk/sudoku/forum/viewtopic.php?f=13&t=1394 |
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Author: | h3lix [ Thu Dec 01, 2016 10:56 pm ] |
Post subject: | Butterfly X Nurikabe Killer |
Here's another take on an idea I came up with 9 years ago on the djape forums, a killer puzzle where cages are given as Nurikabe clues. Since there is very little cage coverage, the grid has to be very tightly constrained. The puzzle I made then consisted of a pair of grids that had the same solution. This puzzle is made up of four overlapping 9x9 sudoku grids arranged in a butterfly pattern (1 in each corner), each with it's own set of main diagonals. The sum/size of all cages are given, but not their shapes. The shapes of cages must form islands in a valid Nurikabe solution. Givens are shaded, and thus cannot be part of a cage. Here's the puzzle: Hidden Text: |
Author: | Andrew [ Fri Dec 02, 2016 2:22 am ] |
Post subject: | Re: Butterfly X Nurikabe Killer |
Not sure whether I'll try this puzzle. But one question anyway. Are the cages constrained to be completely within one of the four Sudoku grids? My guess is that they are. |
Author: | h3lix [ Fri Dec 02, 2016 3:24 am ] |
Post subject: | Re: Butterfly X Nurikabe Killer |
There is no constraint about cages being completely within 1 of the four grids. |
Author: | wellbeback [ Thu Dec 15, 2016 4:11 am ] |
Post subject: | Re: Butterfly X Nurikabe Killer |
Whew. One of the hardest puzzles I've ever managed to complete. Took me days! First Nurikabe puzzle for me so maybe it would have been easier if I knew the techniques for them. I'm not even going to attempt a WT. But here is my solution. White cells are the walls. Thanks h3lix! Happy Holidays to all. Solution: |
Author: | HATMAN [ Tue Mar 28, 2017 1:08 pm ] |
Post subject: | Re: Butterfly X Nurikabe Killer |
wellbeback How did you get started? I've looked at the puzzle and your solution and other than r1c1 being {3/5/7/9} I cannot see how to start. Maurice |
Author: | wellbeback [ Thu Mar 30, 2017 5:18 pm ] |
Post subject: | Re: Butterfly X Nurikabe Killer |
Hi Maurice In the following I identify nonets by row and column. e.g., n13 contains 8 in cell 1. I identify cells in a nonet with a capital 'C'. e.g., We are given n13C1 = 8 Note that the cells that are given values in the puzzle are wall cells. General rules. 1. For an edge nonet the cell values must match in the same row or column in the opposite edge nonet. e.g.: 2. Every cell is either a wall cell or a cage cell. Cages cannot be orthogonally adjacent. -> Where known cells from different cages are separated by a single cell - that cell must be a wall cell. E.g., n12C6 and n12C8 must be wall cells. Similarly where known different cage cells are diagonally adjacent - the cells adjacent to both those cage cells must be wall cells. E.g., n23C6, n24C7, and n33C3 must be wall cells. 3. All wall cells in the whole puzzle form a continuous chain. -> E.g., n24C8 must be a wall cell. 4. Remember that there cannot be any block of wall cells larger than 2x2. More: How I started... Starting...: |
Author: | HATMAN [ Mon Apr 03, 2017 11:26 am ] |
Post subject: | Re: Butterfly X Nurikabe Killer |
Thanks wellbeback I'll go through it at the weekend |
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