The Bridges of Königsberg
(Published on 15. April 2024, 17:07 by josebastian8)
- Normal sudoku rules apply.
- The river (blue line) is a region sum line: box borders divide it into segments of equal sum.
- The bridges (green lines) are 3-cells long German whispers: adjacent digits along the line must have a difference of at least 5.
- Euler Walk: Euler wants to go from the university (north district) to his home (south district). To do so, he must cross ALL the bridges, but only ONCE each (he can cross the river only via a bridge). If necessary, you may add one more bridge, but it cannot share a cell with any other one.
Link
Solution code: Row 1 followed by row 9 (No spaces)
Comments
on 18. April 2024, 13:30 by Al Fresco
Nice puzzle concept and some lovely logic throughout:)
on 15. April 2024, 21:51 by josebastian8
For anyone who doesn't know how to start the puzzle or haven't heard of this problem before, I recommend searching for it on Wikipedia or other math source. Those who know, don't spoil the solution here please!
on 15. April 2024, 20:52 by Big Tiger
Well, I'm hopelessly stuck anyway - can't even get a first digit.
on 15. April 2024, 19:18 by Big Tiger
Am I missing something or ... does the "Euler Walk" have absolutely nothing to do with the Sudoku numbers? Aside from "he must cross every bridge", I don't see any restrictions on the layout of his path...
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@Big Tiger, this is a classic problem in graph theory, a math field. Try to find such a path, or deduce what conditions you need to make it exist. If you keep on struggling, search for it on Wikipedia.
