## 2010 C3

Discussion on International Mathematical Olympiad (IMO)
Kazi_Zareer
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### 2010 C3

$2500$ chess kings have to be placed on a $100 \times 100$ chessboard so that
(i) no king can capture any other one (i.e. no two kings are placed in two squares sharing a common vertex);
(ii) each row and each column contains exactly $25$ kings.

Find the number of such arrangements. (Two arrangements differing by rotation or symmetry are supposed to be different.)
Last edited by Phlembac Adib Hasan on Mon Aug 08, 2016 8:54 am, edited 1 time in total.
Reason: Latexed and given appropriate title
We cannot solve our problems with the same thinking we used when we create them.