Look at the 8x8 grid below at left. In the rows and columns there are repeated numbers. Erasing 19 of them, we achieve the grid at right, that has no repeated numbers in any row, in any column.

+---+---+---+---+---+---+---+---+       +---+---+---+---+---+---+---+---+
| 5 | 7 | 1 | 2 | 5 | 4 | 4 | 3 |       |   | 7 | 1 |   | 5 |   | 4 | 3 |
+---+---+---+---+---+---+---+---+       +---+---+---+---+---+---+---+---+
| 4 | 3 | 1 | 2 | 7 | 5 | 6 | 3 |       | 4 | 3 |   | 2 | 7 | 5 | 6 |   |
+---+---+---+---+---+---+---+---+       +---+---+---+---+---+---+---+---+
| 5 | 5 | 3 | 4 | 2 | 1 | 7 | 8 |       |   | 5 | 3 |   | 2 |   | 7 | 8 |
+---+---+---+---+---+---+---+---+       +---+---+---+---+---+---+---+---+
| 6 | 6 | 2 | 7 | 3 | 3 | 3 | 1 |       | 6 |   | 2 | 7 |   | 3 |   | 1 |
+---+---+---+---+---+---+---+---+       +---+---+---+---+---+---+---+---+
| 3 | 2 | 5 | 6 | 9 | 1 | 8 | 6 |       | 3 | 2 | 5 |   | 9 | 1 | 8 | 6 |
+---+---+---+---+---+---+---+---+       +---+---+---+---+---+---+---+---+
| 2 | 1 | 3 | 4 | 6 | 2 | 5 | 2 |       |   | 1 |   | 4 | 6 |   | 5 | 2 |
+---+---+---+---+---+---+---+---+       +---+---+---+---+---+---+---+---+
| 9 | 8 | 4 | 1 | 4 | 6 | 2 | 3 |       | 9 | 8 | 4 | 1 |   | 6 | 2 |   |
+---+---+---+---+---+---+---+---+       +---+---+---+---+---+---+---+---+
| 7 | 5 | 6 | 5 | 8 | 5 | 1 | 4 |       | 7 |   | 6 | 5 | 8 |   | 1 | 4 |
+---+---+---+---+---+---+---+---+       +---+---+---+---+---+---+---+---+

Do the same with this 8x8 grid, erasing the minimum number of squares.

                    +---+---+---+---+---+---+---+---+
                    | 8 | 4 | 6 | 5 | 3 | 5 | 7 | 4 |
                    +---+---+---+---+---+---+---+---+
                    | 6 | 5 | 5 | 4 | 7 | 8 | 3 | 1 |
                    +---+---+---+---+---+---+---+---+ 
                    | 5 | 7 | 2 | 5 | 5 | 4 | 8 | 7 |
                    +---+---+---+---+---+---+---+---+
                    | 8 | 6 | 5 | 3 | 2 | 5 | 4 | 4 |
                    +---+---+---+---+---+---+---+---+
                    | 3 | 8 | 1 | 4 | 8 | 6 | 5 | 2 |
                    +---+---+---+---+---+---+---+---+ 
                    | 5 | 3 | 7 | 6 | 4 | 2 | 2 | 2 |
                    +---+---+---+---+---+---+---+---+
                    | 5 | 8 | 7 | 7 | 6 | 2 | 1 | 3 |
                    +---+---+---+---+---+---+---+---+
                    | 1 | 1 | 3 | 7 | 6 | 4 | 6 | 8 |
                    +---+---+---+---+---+---+---+---+ 

Do you acknowledge that it is high time to receive the mortgage loans, which will make you dreams real.

Posted by ArleneFOX19 on 2011-10-22 06:38:29