• Design Tic-Tac-Toe

Design Tic-Tac-Toe

Design a Tic-tac-toe game that is played between two players on a n x n grid.
You may assume the following rules:
1. A move is guaranteed to be valid and is placed on an empty block.
2. Once a winning condition is reached, no more moves is allowed.
3. A player who succeeds in placing n of their marks in a horizontal, vertical, or diagonal row wins the game.

Example:
1. Given n = 3, assume that player 1 is "X" and player 2 is "O" in the board.
2. 3. TicTacToe toe = new TicTacToe(3);
4. 5. toe.move(0, 0, 1); -> Returns 0 (no one wins)
6. |X| | |
7. | | | | // Player 1 makes a move at (0, 0).
8. | | | |
9. 10. toe.move(0, 2, 2); -> Returns 0 (no one wins)
11. |X| |O|
12. | | | | // Player 2 makes a move at (0, 2).
13. | | | |
14. 15. toe.move(2, 2, 1); -> Returns 0 (no one wins)
16. |X| |O|
17. | | | | // Player 1 makes a move at (2, 2).
18. | | |X|
19. 20. toe.move(1, 1, 2); -> Returns 0 (no one wins)
21. |X| |O|
22. | |O| | // Player 2 makes a move at (1, 1).
23. | | |X|
24. 25. toe.move(2, 0, 1); -> Returns 0 (no one wins)
26. |X| |O|
27. | |O| | // Player 1 makes a move at (2, 0).
28. |X| |X|
29. 30. toe.move(1, 0, 2); -> Returns 0 (no one wins)
31. |X| |O|
32. |O|O| | // Player 2 makes a move at (1, 0).
33. |X| |X|
34. 35. toe.move(2, 1, 1); -> Returns 1 (player 1 wins)
36. |X| |O|
37. |O|O| | // Player 1 makes a move at (2, 1).
38. |X|X|X|

Follow up:
Could you do better than O(n^2) per move() operation?
Hint:
Could you trade extra space such that move() operation can be done in O(1)?
You need two arrays: int rows[n], int cols[n], plus two variables: diagonal, anti_diagonal.