Valid Tic-Tac-Toe State
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Description
Given a Tic-Tac-Toe board as a string array board, return true if and only if it is possible to reach this board position during the course of a valid tic-tac-toe game.
The board is a 3 x 3 array that consists of characters ' ', 'X', and 'O'. The ' ' character represents an empty square.
Here are the rules of Tic-Tac-Toe:
- Players take turns placing characters into empty squares ' '.
- The first player always places 'X' characters, while the second player always places 'O' characters.
- 'X' and 'O' characters are always placed into empty squares, never filled ones.
- The game ends when there are three of the same (non-empty) character filling any row, column, or diagonal.
- The game also ends if all squares are non-empty.
- No more moves can be played if the game is over.
Example 1:
Example 2:
Example 3:
Solution