Another case of circles and crosses. Place two crosses on two cells of each row and column of this 9×9 board, and circles elsewhere, so that the number on the right of each row indicates the number of circles between its two crosses, while the number below each column indicates the number of circles between its two crosses.

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1 Answer 1


(I'll be using shading for easier visibility and solving: shaded cells are crosses, unshaded cells are circles.)

Step 1:

Size-5 rows cannot have a cross in the middle three cells. Size-4 rows can't have one in the middle cell.

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This gives us row 5, which rules out most cells in column 8.
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Step 2:

Now, the second and third cells from the bottom in the last column cannot be shaded: they would break their rows. So this gives us the last column, and many more cells can be placed easily from there.

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There's only one possibility for the first column. The rest of the puzzle follows easily from that.

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  • 4
    $\begingroup$ aargh, ninjaed as usual :-). $\endgroup$
    – Gareth McCaughan
    Oct 29, 2019 at 17:13
  • $\begingroup$ Yep. Me too. :( Nice work! $\endgroup$
    – Trenin
    Oct 29, 2019 at 17:28

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