The Will-Never-Lose-TicTacToe Strategy

Applying the following rules in the given order. If any rule is selected then the subsequent rules are ignored. Note: m: computer's symbol, n: user's symbol

Rule#1: See if the computer can win.
Rule#2: Block the users winning slot.
Rule#3: Now here you can play some tricks.

a) If n is the only symbol and and not in the
center then occupy the center.

b) If the board is blank put m on any corner.
Subsequently (i.e. in next step), put m in any
position such that number of winning positions
for m is 0.

Rule#4: Find a list of all those positions where placing
an n would result in two winning positions for
the user. Put m in a position which makes a winning
position not belonging to this list.

Rule#5: Find a position where placing an m
would result in two winning positions.

Rule#6: Put a m such that it results in one
winning position, if possible in the center.

Rule#7: Put a m in any blank place.
Rule#8: return ERROR, this should ideally not execute

This strategy has been used by the TicTacToe class and ensures that the computer will never lose!

Strategy designed by Bhurvi and me.