answer (圖)

來源: compound 於 2009-05-01 17:38:45 [] [舊帖] [給我悄悄話] 閱讀數 : (349 bytes)

4x4=16 gives the basic grid (see the picture), to which you can remove 1 or 3 row and column to satisfy the requirement: keep any one unit square to share only one side of red unit. Then 503x4 = 2012 gives 2012x2012 grid, to which remove 3 row and column to get 2009x2009 grid.

所有跟帖： 

• sorry, it 20grid. Then 101x20 =2020, remove 11 can be done. -compound- ♂ 給 compound 發送悄悄話 (0 bytes) () 05/01/2009 postreply 17:47:07

• it works only by removing odd number of row or column. -compound- ♂ 給 compound 發送悄悄話 (0 bytes) () 05/01/2009 postreply 17:54:38

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