/**
     * Function name:  checkLeft
     * @param board
     * @return count (int)
     * Inside the function
     *  1. using single loop to check the left diagnol to check same X/O
     * 
     */
    public static int checkLeft(char[][] board){
        int count =0;
        for(int i=0; i<board.length;i++){
            if(board[i][i]=='X'){
                count++;
            }
            else if(board[i][i]=='O'){
                count--;
            }
        }
        if(count==3|| count==-3){
            return count;
        }
        else {
            count =0;
        }
        return count;
    }