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## #1 2014-11-04 07:16:17

EdV56
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From: Minneapolis
Registered: 2014-10-17
Posts: 20
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### Determining Number of Rows in an Exact Cover Matrix

Hi,
can someone help me understand how the author arrived at 2222 rows for the exact cover matrix in this article?

Puzzling Over Exact Cover Problems

http://www.ams.org/samplings/feature-co … c-kanoodle

Given an exact cover matrix consisting of:

1. 67 columns: one for each of the 12 Kanoodle pieces and one for each cell in the 5 by 11 grid.

2. 12 Rows per solution corresponding to the 12 Kanoodle pieces.

3. A solution is 12 pieces placed filling the 5 by 11 grid

"We will therefore have one row in our matrix for each possible placement of each of the 12 pieces, which leads to 2222 rows."

I don't understand how the author arrived at 2222 rows

Thanks!

Eschew obfuscation!

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