Problem
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:
Input: board = ["O "," "," "] Output: false Explanation: The first player always plays "X".
Example 2:
Input: board = ["XOX"," X "," "] Output: false Explanation: Players take turns making moves.
Example 3:
Input: board = ["XOX","O O","XOX"] Output: true
Constraints:
- board.length == 3
- board[i].length == 3
- board[i][j]is either- 'X',- 'O', or- ' '.