New answers tagged combinatorics
3
The sawtooth rule gives us some super powerful tools. The other answer uses them, but doesn't outright abuse them, so here's another approach that does.
Analyzing the constraints
By sudoku, we know there will be a row in the grid that has a nine in the second column. That row is severely restricted, it's basically just all the digits in descending order, ...
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Solution:
Took 1 hour and 35 minutes according to the timer!
(For all images, click/open in new tab for a larger, clearer version)
Let's start off by ignoring the sawtooth rule for now, and focusing on the XV conditions:
One last key image before we start filling in numbers:
Now we can start adding some numbers:
A few more numbers:
Now let's look at ...
3
A stronger solution.
Here is an illustration of the process.
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