Coach Thrasher

Gridflip Solution

There's a fun puzzle called Grid Flip on Facebook that had me distracted for a while.

Here's my solution:

S = 1624

Which is produced by the grid:

[   33   30  -10   -6   18    7  -11  -23    6 ]    44

[  -16   19    9   26    8  -19    8  -21  -14 ]     0

[  -17  -12  -14  -31   30   13   13   19   16 ]    17

[    6   11    1  -17   12   -4    7   14  -21 ]     9

[  -18   31   34   22  -17  -19  -20   24    6 ]    43

[  -33   18   17   15  -31   -5   -3   27   -3 ]     2

[   18   20  -18  -31   -6    4    2  -12   24 ]     1

[  -27  -14    4   29    3    5   29    8  -12 ]    25

[  -15   -7   23   23   -9    8    6   -8   12 ]    33

[   33  -23   19   -4   -8    7   11   12  -31 ]    16

[   20  -19  -15   30  -11   32   -7   14   -5 ]    39

[   23  -18  -32    2   31   -7   -8   24   16 ]    31

[  -32    4  -10   14    6   -1    0   23   23 ]    27

[   25    0   23   22   12  -28  -27  -15   -4 ]     8

[  -30  -13   16   -3   -3   32   -3  -27   31 ]     0

[   22    1  -26    4   -2   13   26  -17  -14 ]     7

[    9   18    3   20   27  -32   11   27   13 ]    96

[   17  -33   -7  -19   32   13   31   -2  -24 ]     8

[  -31   27   31  -29   15   -2   29   15  -33 ]    22

[   18   23   15  -28    0   30    4   12  -32 ]    42

[    3  -34   27   25   18   26   -1   34   26 ]   124

[   21   31  -10   13   30  -17   12  -26   31 ]    85

[   23  -31   19   21  -17   10    2   23  -23 ]    27

[    3   -6    0    3   32    0   10  -25   14 ]    31

[   19   -9   14   27  -20   15    5  -27   18 ]    42

[   11   -6  -24    7  -17  -26   20   31   25 ]    21

[  -25    4   16   30   33  -23   -4    4  -23 ]    12



    60   12  105  165  166   32  142  108   22    1624

The shortest possible sequence of such calls which achieves this value S while
satisfying the non-negative property for all elements in SC and SR using
15 steps is:

flip_col(1)
flip_col(2)
flip_col(4)
flip_col(5)
flip_col(7)
flip_row(1)
flip_row(9)
flip_row(10)
flip_row(14)
flip_row(15)
flip_row(16)
flip_row(19)
flip_row(23)
flip_row(26)
flip_row(27)

Posted at 11:07PM Sep 08, 2007 by jason in General  |