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Algorithm for playing Tic-Tac-Toe

Take a tic-tac-toe square, and value the squares as follows:

2|1|2

_____

1|3|1

_____

2|1|2

For each possible square you can pick in a move, add the values for each full row, column, or diagonal that it is on (a "full" row or diagonal means having 3 squares, occupied or not), adding 2 for each marker of your own on that row, column, or diagonal, and 1 for each marker of your opponent on that row, column, or diagonal. Then multiply by -1 for each opponent's marker on that row, column, or diagonal [*]. Take the square with the highest value; choose randomly among squares when there are ties for highest value.

So, initially, before any markers are placed, the cells will have the values:

17|10|17

________

10|24|10

________

17|10|17

The center, having a value of 24, will always be taken first.

 | |

_____

 |X|

_____

 | |  

The proper response for O, looking at the values:
Upper Left Square:
Add left column: 2+1+2 = 5
Add top row: 2+1+2 = 5
Add diagonal: (2+3(for square)+1(for opponent marker on square)+2) x -1 = -8
5+5-8 = 2

Upper Middle Square:
Add top row: 2+1+2 = 5
Add center column: (1+3(for square)+1(for opponent marker on square)+1)x-1= -6
5-6 = -1

Upper Right Square:
Add right column: 2+1+2 = 5
Add top row: 2+1+2 = 5
Add diagonal: (2+3(for square)+1(for opponent marker on square)+2) x -1 = -8
5+5-8 = 2

Middle Left Square:
Add left column: 2+1+2 = 5
Add middle row: (1+3(for square)+1(for opponent marker on square)+1)x-1= -6
5-6 = -1

Middle Right Square:
Add right column: 2+1+2 = 5
Add middle row: (1+3(for square)+1(for opponent marker on square)+1)x-1= -6
5-6 = -1

Lower Left Square:
Add left column: 2+1+2 = 5
Add bottom row: 2+1+2 = 5
Add diagonal: (2+3(for square)+1(for opponent marker on square)+2) x -1 = -8
5+5-8 = 2

Lower Middle Square:
Add bottom row: 2+1+2 = 5
Add center column: (1+3(for square)+1(for opponent marker on square)+1)x-1= -6
5-6 = -1

Upper Right Square:
Add right column: 2+1+2 = 5
Add bottom row: 2+1+2 = 5
Add diagonal: (2+3(for square)+1(for opponent marker on square)+2) x -1 = -8
5+5-8 = 2

So, since any of the corners have a value of 2, which is the highest value, randomly pick one.


And so on.




Yeah, the things I do for fun on Saturday... wild, huh?

If you see a hole in my algorithm, point it out, I just did it while sitting here, but it looks good to me...




[*] you'll note that means that two markers of the opponent cancel out each other's multiplication effect.