74th LeetCode Weekly Contest Valid Tic-Tac-Toe State

A Tic-Tac-Toe board is given 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, and 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 3 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 = ["XXX", "   ", "OOO"]
Output: false

Example 4:
Input: board = ["XOX", "O O", "XOX"]
Output: true

Note:

• board is a length-3 array of strings, where each string board[i] has length 3.
• Each board[i][j] is a character in the set {" ", "X", "O"}.

 判断井字棋是不是合法状态，想怎么判断就怎么判断吧

class Solution {
public:
    char Board[3][3];
    bool check(int x,int y,int dx,int dy,char c){
        for(int i=0;i<3;i++){
            if(Board[x][y]!=c){
                return 0;
            }
            x+=dx;
            y+=dy;
        }
        return 1;
    }
    bool win(char a){
        for(int i=0;i<3;i++){
            if(check(0,i,1,0,a)){     
                return 1;
            }
            if(check(i,0,0,1,a)){
                return 1;
            }
        }
        if(check(0,0,1,1,a)){
            return 1;
        }
        if(check(0,2,1,-1,a)){
            return 1;
        }
        return 0;
    }
    bool validTicTacToe(vector<string>& board) {
        
        
        int X=0;
        int O=0;
        int len=board.size();
        for(int i=0;i<len;i++){
            
            for(int j=0;j<3;j++){
               
                    Board[i][j]=board[i][j];
                
                if(Board[i][j]=='X'){
                    X++;
                }
                if(Board[i][j]=='O'){
                    O++;
                }
            }
          //  Str="";
        }
        if(X!=O&&O+1!=X){
            return false;
        }
        int x=win('X');
        int o=win('O');
        if(o+x>=2){
            return false;
        }
        // for(int i=0;i<3;i++){
        //     for(int j=0;j<3;j++){
        //         cout<<Board[i][j];
        //     }
        //     cout<<endl;
        // }
        if(x){
            return X==(O+1);
        }
        if(o){
            //cout<<o<<endl;
            return X==O;
        }
        return true;
    }
};